1
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Bhosale S, Deen MC, Proceviat C, Hettle A, Winter DK, Brockerman J, Levene M, Bennet AJ, Spino C, Boraston AB, Vocadlo DJ. A Fluorogenic Disaccharide Substrate for α-Mannosidases Enables High-Throughput Screening and Identification of an Inhibitor of the GH92 Virulence Factor from Streptococcus pneumoniae. ACS Chem Biol 2023; 18:1730-1737. [PMID: 37531094 DOI: 10.1021/acschembio.3c00053] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
Trimming of host glycans is a mechanism that is broadly employed by both commensal and pathogenic microflora to enable colonization. Host glycan trimming by the opportunistic Gram-positive bacterium Streptococcus pneumoniae has been demonstrated to be an important mechanism of virulence. While S. pneumoniae employs a multitude of glycan processing enzymes, the exo-mannosidase SpGH92 has been shown to be an important virulence factor. Accordingly, SpGH92 is hypothesized to be a target for much-needed new treatments of S. pneumoniae infection. Here we report the synthesis of 4-methylumbelliferyl α-d-mannopyranosyl-(1→2)-β-d-mannopyranoside (Manα1,2Manβ-4MU) as a fluorogenic disaccharide substrate and development of an assay for SpGH92 that overcomes its requirement for +1 binding site occupancy. We miniaturize our in vitro assay and apply it to a high-throughput screen of >65 000 compounds, identifying a single inhibitory chemotype, LIPS-343. We further show that Manα1,2Manβ-4MU is also a substrate of the human Golgi-localized α-mannosidase MAN1A1, suggesting that this substrate should be useful for assessing the activity of this and other mammalian α-mannosidases.
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Affiliation(s)
- Sandeep Bhosale
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Matthew C Deen
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Cameron Proceviat
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Andrew Hettle
- Department of Biochemistry & Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
| | - Dana K Winter
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Jacob Brockerman
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Marina Levene
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Andrew J Bennet
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Claude Spino
- Département de Chimie, Université de Sherbrooke, Sherbrooke, Québec J1K 2R1, Canada
| | - Alisdair B Boraston
- Department of Biochemistry & Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6, Canada
| | - David J Vocadlo
- Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
- Department of Molecular Biology and Biochemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
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2
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Alvarez MRS, Grijaldo SJB, Nacario RC, Rabajante JF, Heralde FM, Lebrilla CB, Completo GC. In silico screening-based discovery of inhibitors against glycosylation proteins dysregulated in cancer. J Biomol Struct Dyn 2023; 41:1540-1552. [PMID: 34989310 DOI: 10.1080/07391102.2021.2022534] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Targeting enzymes associated with the biosynthesis of aberrant glycans is an under-utilized strategy in discovering potential inhibitors or drugs against cancer. The formation of cancer-associated glycans is mainly due to the dysregulated expression of glycosyltransferases and glycosidases, which play crucial roles in maintaining cellular structure and function. We screened a database of more than 14,000 compounds consisting of natural products and drugs for inhibition against four glycosylation enzymes - Alpha1-6FucT, ST6Gal1, ERMan1, and GlcNAcT-V. The top inhibitors identified against each enzyme were subsequently analyzed for potential binding against all four enzymes. In silico screening results show several promising candidates that could potentially inhibit all four enzymes: (1) Amb20622156 (demethylwedelolactone) [ERMan1: -9.3 kcal/mol; Alpha1-6FucT: -7.3 kcal/mol; ST6Gal1: -8.4 kcal/mol; GlcNAcT-V: -7.2 kcal/mol], (2) Amb22173588 (1,2-dihydrotanshinone I) [ERMan1: -9.3 kcal/mol; Alpha1-6FucT: -6.1 kcal/mol; ST6Gal1: -9.2 kcal/mol; GlcNAcT-V: -7.9 kcal/mol], and (3) Amb22173591 (tanshinol B) [ERMan1: -9.3 kcal/mol; Alpha1-6FucT: -6.0 kcal/mol; ST6Gal1: -9.8 kcal/mol; GlcNAcT-V: -7.7 kcal/mol]. Drug-enzyme active site residue interaction analyses show that the putative inhibitors form non-covalent bonding interactions with key active site residues in each enzyme, suggesting critical target residues in the four enzymes' active sites. Furthermore, pharmacokinetic property prediction analysis using pkCSM indicates that all of these inhibitors have good ADMETox properties (i.e., log P < 5, Caco-2 permeability > 0.90, intestinal absorption > 30%, skin permeability>-2.5, CNS permeability <-3, maximum tolerated dose < 0.477, minnow toxicity<-0.3). The in silico docking approach to glycosylation enzyme inhibitor prediction could help guide and streamline the discovery of novel inhibitors against enzymes involved in aberrant protein glycosylation.Communicated by Ramaswamy H. Sarma.
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Affiliation(s)
- Michael Russelle S Alvarez
- Institute of Chemistry, University of the Philippines Los Baños, Los Baños, Laguna, Philippines.,College of Arts and Sciences, Isabela State University, Echague, Isabela, Philippines
| | - Sheryl Joyce B Grijaldo
- Institute of Chemistry, University of the Philippines Los Baños, Los Baños, Laguna, Philippines
| | - Ruel C Nacario
- Institute of Chemistry, University of the Philippines Los Baños, Los Baños, Laguna, Philippines
| | - Jomar F Rabajante
- Institute of Mathematical Sciences and Physics, University of the Philippines Los Baños, Los Baños, Laguna, Philippines
| | - Francisco M Heralde
- Molecular Diagnostics and Cellular Therapeutics Laboratory, Lung Center of the Philippines, Quezon City, Philippines
| | - Carlito B Lebrilla
- Department of Chemistry, University of California Davis, Davis, California, USA
| | - Gladys C Completo
- Institute of Chemistry, University of the Philippines Los Baños, Los Baños, Laguna, Philippines
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3
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Cruz Marino T, Leblanc J, Pratte A, Tardif J, Thomas MJ, Fortin CA, Girard L, Bouchard L. Portrait of autosomal recessive diseases in the French-Canadian founder population of Saguenay-Lac-Saint-Jean. Am J Med Genet A 2023; 191:1145-1163. [PMID: 36786328 DOI: 10.1002/ajmg.a.63147] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/15/2023]
Abstract
The population of the Saguenay-Lac-Saint-Jean (SLSJ) region, located in the province of Quebec, Canada, is recognized as a founder population, where some rare autosomal recessive diseases show a high prevalence. Through the clinical and molecular study of 82 affected individuals from 60 families, this study outlines 12 diseases identified as recurrent in SLSJ. Their carrier frequency was estimated with the contribution of 1059 healthy individuals, increasing the number of autosomal recessive diseases with known carrier frequency in this region from 14 to 25. We review the main clinical and molecular features previously reported for these disorders. Five of the studied diseases have a potential lethal effect and three are associated with intellectual deficiency. Therefore, we believe that the provincial program for carrier screening should be extended to include these eight disorders. The high-carrier frequency, together with the absence of consanguinity in most of these unrelated families, suggest a founder effect and genetic drift for the 12 recurrent variants. We recommend further studies to validate this hypothesis, as well as to extend the present study to other regions in the province of Quebec, since some of these disorders could also be present in other French-Canadian families.
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Affiliation(s)
- Tania Cruz Marino
- Department of Laboratory Medicine, CIUSSS Saguenay-Lac-St-Jean, Quebec, Canada
| | - Josianne Leblanc
- Department of Laboratory Medicine, CIUSSS Saguenay-Lac-St-Jean, Quebec, Canada
| | - Annabelle Pratte
- Department of Laboratory Medicine, CIUSSS Saguenay-Lac-St-Jean, Quebec, Canada
| | - Jessica Tardif
- Department of Laboratory Medicine, CIUSSS Saguenay-Lac-St-Jean, Quebec, Canada
| | | | - Carol-Ann Fortin
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences (FMHS), Université de Sherbrooke, Quebec, Canada
| | - Lysanne Girard
- Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences (FMHS), Université de Sherbrooke, Quebec, Canada
| | - Luigi Bouchard
- Department of Laboratory Medicine, CIUSSS Saguenay-Lac-St-Jean, Quebec, Canada.,Department of Biochemistry and Functional Genomics, Faculty of Medicine and Health Sciences (FMHS), Université de Sherbrooke, Quebec, Canada
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4
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Kemme L, Grüneberg M, Reunert J, Rust S, Park J, Westermann C, Wada Y, Schwartz O, Marquardt T. Translational balancing questioned: Unaltered glycosylation during disulfiram treatment in mannosyl-oligosaccharide alpha-1,2-mannnosidase-congenital disorders of glycosylation (MAN1B1-CDG). JIMD Rep 2021; 60:42-55. [PMID: 34258140 PMCID: PMC8260486 DOI: 10.1002/jmd2.12213] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2020] [Revised: 02/27/2021] [Accepted: 03/02/2021] [Indexed: 12/25/2022] Open
Abstract
MAN1B1-CDG is a multisystem disorder caused by mutations in MAN1B1, encoding the endoplasmic reticulum mannosyl-oligosaccharide alpha-1,2-mannnosidase. A defect leads to dysfunction within the degradation of misfolded glycoproteins. We present two additional patients with MAN1B1-CDG and a resulting defect in endoplasmic reticulum-associated protein degradation. One patient (P2) is carrying the previously undescribed p.E663K mutation. A therapeutic trial in patient 1 (P1) using disulfiram with the rationale to generate an attenuation of translation and thus a balanced, restored ER glycoprotein synthesis failed. No improvement of the transferrin glycosylation profile was seen.
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Affiliation(s)
- Lisa Kemme
- University Children's Hospital MünsterMuensterGermany
| | | | | | - Stephan Rust
- University Children's Hospital MünsterMuensterGermany
| | - Julien Park
- University Children's Hospital MünsterMuensterGermany
- Department of Clinical Sciences, NeurosciencesUmeå UniversityUmeåSweden
| | - Cordula Westermann
- Gerhard‐Domagk‐Institute of PathologyUniversity Hospital MuensterMuensterGermany
| | - Yoshinao Wada
- Osaka Medical Center and Research Institute for Maternal and Child HealthOsakaJapan
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5
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Abstract
Folding of proteins is essential so that they can exert their functions. For proteins that transit the secretory pathway, folding occurs in the endoplasmic reticulum (ER) and various chaperone systems assist in acquiring their correct folding/subunit formation. N-glycosylation is one of the most conserved posttranslational modification for proteins, and in eukaryotes it occurs in the ER. Consequently, eukaryotic cells have developed various systems that utilize N-glycans to dictate and assist protein folding, or if they consistently fail to fold properly, to destroy proteins for quality control and the maintenance of homeostasis of proteins in the ER.
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Ninagawa S, George G, Mori K. Mechanisms of productive folding and endoplasmic reticulum-associated degradation of glycoproteins and non-glycoproteins. Biochim Biophys Acta Gen Subj 2020; 1865:129812. [PMID: 33316349 DOI: 10.1016/j.bbagen.2020.129812] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 12/09/2020] [Accepted: 12/09/2020] [Indexed: 12/22/2022]
Abstract
BACKGROUND The quality of proteins destined for the secretory pathway is ensured by two distinct mechanisms in the endoplasmic reticulum (ER): productive folding of newly synthesized proteins, which is assisted by ER-localized molecular chaperones and in most cases also by disulfide bond formation and transfer of an oligosaccharide unit; and ER-associated degradation (ERAD), in which proteins unfolded or misfolded in the ER are recognized and processed for delivery to the ER membrane complex, retrotranslocated through the complex with simultaneous ubiquitination, extracted by AAA-ATPase to the cytosol, and finally degraded by the proteasome. SCOPE OF REVIEW We describe the mechanisms of productive folding and ERAD, with particular attention to glycoproteins versus non-glycoproteins, and to yeast versus mammalian systems. MAJOR CONCLUSION Molecular mechanisms of the productive folding of glycoproteins and non-glycoproteins mediated by molecular chaperones and protein disulfide isomerases are well conserved from yeast to mammals. Additionally, mammals have gained an oligosaccharide structure-dependent folding cycle for glycoproteins. The molecular mechanisms of ERAD are also well conserved from yeast to mammals, but redundant expression of yeast orthologues in mammals has been encountered, particularly for components involved in recognition and processing of glycoproteins and components of the ER membrane complex involved in retrotranslocation and simultaneous ubiquitination of glycoproteins and non-glycoproteins. This may reflect an evolutionary consequence of increasing quantity or quality needs toward mammals. GENERAL SIGNIFICANCE The introduction of innovative genome editing technology into analysis of the mechanisms of mammalian ERAD, as exemplified here, will provide new insights into the pathogenesis of various diseases.
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Affiliation(s)
- Satoshi Ninagawa
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
| | - Ginto George
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan
| | - Kazutoshi Mori
- Department of Biophysics, Graduate School of Science, Kyoto University, Kyoto 606-8502, Japan.
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7
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The cytoplasmic tail of human mannosidase Man1b1 contributes to catalysis-independent quality control of misfolded alpha1-antitrypsin. Proc Natl Acad Sci U S A 2020; 117:24825-24836. [PMID: 32958677 DOI: 10.1073/pnas.1919013117] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The failure of polypeptides to achieve conformational maturation following biosynthesis can result in the formation of protein aggregates capable of disrupting essential cellular functions. In the secretory pathway, misfolded asparagine (N)-linked glycoproteins are selectively sorted for endoplasmic reticulum-associated degradation (ERAD) in response to the catalytic removal of terminal alpha-linked mannose units. Remarkably, ER mannosidase I/Man1b1, the first alpha-mannosidase implicated in this conventional N-glycan-mediated process, can also contribute to ERAD in an unconventional, catalysis-independent manner. To interrogate this functional dichotomy, the intracellular fates of two naturally occurring misfolded N-glycosylated variants of human alpha1-antitrypsin (AAT), Null Hong Kong (NHK), and Z (ATZ), in Man1b1 knockout HEK293T cells were monitored in response to mutated or truncated forms of transfected Man1b1. As expected, the conventional catalytic system requires an intact active site in the Man1b1 luminal domain. In contrast, the unconventional system is under the control of an evolutionarily extended N-terminal cytoplasmic tail. Also, N-glycans attached to misfolded AAT are not required for accelerated degradation mediated by the unconventional system, further demonstrating its catalysis-independent nature. We also established that both systems accelerate the proteasomal degradation of NHK in metabolic pulse-chase labeling studies. Taken together, these results have identified the previously unrecognized regulatory capacity of the Man1b1 cytoplasmic tail and provided insight into the functional dichotomy of Man1b1 as a component in the mammalian proteostasis network.
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8
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Rovira C, Males A, Davies GJ, Williams SJ. Mannosidase mechanism: at the intersection of conformation and catalysis. Curr Opin Struct Biol 2019; 62:79-92. [PMID: 31891872 DOI: 10.1016/j.sbi.2019.11.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2019] [Revised: 10/06/2019] [Accepted: 11/15/2019] [Indexed: 12/17/2022]
Abstract
Mannosidases are a diverse group of enzymes that are important in the biological processing of mannose-containing polysaccharides and complex glycoconjugates. They are found in 12 of the >160 sequence-based glycosidase families. We discuss evidence that nature has evolved a small set of common mechanisms that unite almost all of these mannosidase families. Broadly, mannosidases (and the closely related rhamnosidases) perform catalysis through just two conformations of the oxocarbenium ion-like transition state: a B2,5 (or enantiomeric 2,5B) boat and a 3H4 half-chair. This extends to a new family (GT108) of GDPMan-dependent β-1,2-mannosyltransferases/phosphorylases that perform mannosyl transfer through a boat conformation as well as some mannosidases that are metalloenzymes and require divalent cations for catalysis. Yet, among this commonality lies diversity. New evidence shows that one unique family (GH99) of mannosidases use an unusual mechanism involving anchimeric assistance via a 1,2-anhydro sugar (epoxide) intermediate.
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Affiliation(s)
- Carme Rovira
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, Martí i Franquès 1, 08028 Barcelona, Spain; Institució Catalana de Recerca i Estudis Avançats (ICREA), Pg. Lluís Companys 23, 08010 Barcelona, Spain.
| | - Alexandra Males
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Gideon J Davies
- Department of Chemistry, University of York, Heslington, York YO10 5DD, United Kingdom
| | - Spencer J Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria 3010, Australia.
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9
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Thompson AJ, Spears RJ, Zhu Y, Suits MDL, Williams SJ, Gilbert HJ, Davies GJ. Bacteroides thetaiotaomicron generates diverse α-mannosidase activities through subtle evolution of a distal substrate-binding motif. Acta Crystallogr D Struct Biol 2018; 74:394-404. [PMID: 29717710 PMCID: PMC5930347 DOI: 10.1107/s2059798318002942] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 02/19/2018] [Indexed: 11/17/2022] Open
Abstract
A dominant human gut microbe, the well studied symbiont Bacteroides thetaiotaomicron (Bt), is a glyco-specialist that harbors a large repertoire of genes devoted to carbohydrate processing. Despite strong similarities among them, many of the encoded enzymes have evolved distinct substrate specificities, and through the clustering of cognate genes within operons termed polysaccharide-utilization loci (PULs) enable the fulfilment of complex biological roles. Structural analyses of two glycoside hydrolase family 92 α-mannosidases, BT3130 and BT3965, together with mechanistically relevant complexes at 1.8-2.5 Å resolution reveal conservation of the global enzyme fold and core catalytic apparatus despite different linkage specificities. Structure comparison shows that Bt differentiates the activity of these enzymes through evolution of a highly variable substrate-binding region immediately adjacent to the active site. These observations unveil a genetic/biochemical mechanism through which polysaccharide-processing bacteria can evolve new and specific biochemical activities from otherwise highly similar gene products.
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Affiliation(s)
- Andrew J. Thompson
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Richard J. Spears
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Yanping Zhu
- Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, England
| | - Michael D. L. Suits
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
| | - Spencer J. Williams
- School of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Parkville, Victoria, Australia
| | - Harry J. Gilbert
- Institute for Cell and Molecular Biosciences, Newcastle University, Framlington Place, Newcastle-upon-Tyne NE2 4HH, England
| | - Gideon J. Davies
- Department of Chemistry, University of York, Heslington, York YO10 5DD, England
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10
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Jin ZC, Kitajima T, Dong W, Huang YF, Ren WW, Guan F, Chiba Y, Gao XD, Fujita M. Genetic disruption of multiple α1,2-mannosidases generates mammalian cells producing recombinant proteins with high-mannose-type N-glycans. J Biol Chem 2018; 293:5572-5584. [PMID: 29475941 DOI: 10.1074/jbc.m117.813030] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2017] [Revised: 02/04/2018] [Indexed: 12/27/2022] Open
Abstract
Recombinant therapeutic proteins are becoming very important pharmaceutical agents for treating intractable diseases. Most biopharmaceutical proteins are produced in mammalian cells because this ensures correct folding and glycosylation for protein stability and function. However, protein production in mammalian cells has several drawbacks, including heterogeneity of glycans attached to the produced protein. In this study, we established cell lines with high-mannose-type N-linked, low-complexity glycans. We first knocked out two genes encoding Golgi mannosidases (MAN1A1 and MAN1A2) in HEK293 cells. Single knockout (KO) cells did not exhibit changes in N-glycan structures, whereas double KO cells displayed increased high-mannose-type and decreased complex-type glycans. In our effort to eliminate the remaining complex-type glycans, we found that knocking out a gene encoding the endoplasmic reticulum mannosidase I (MAN1B1) in the double KO cells reduced most of the complex-type glycans. In triple KO (MAN1A1, MAN1A2, and MAN1B1) cells, Man9GlcNAc2 and Man8GlcNAc2 were the major N-glycan structures. Therefore, we expressed two lysosomal enzymes, α-galactosidase-A and lysosomal acid lipase, in the triple KO cells and found that the glycans on these enzymes were sensitive to endoglycosidase H treatment. The N-glycan structures on recombinant proteins expressed in triple KO cells were simplified and changed from complex types to high-mannose types at the protein level. Our results indicate that the triple KO HEK293 cells are suitable for producing recombinant proteins, including lysosomal enzymes with high-mannose-type N-glycans.
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Affiliation(s)
- Ze-Cheng Jin
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Toshihiko Kitajima
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Weijie Dong
- the College of Basic Medical Sciences, Dalian Medical University, Dalian 116044, Liaoning, China, and
| | - Yi-Fan Huang
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Wei-Wei Ren
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Feng Guan
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China
| | - Yasunori Chiba
- the Biotechnology Research Institute for Drug Discovery, National Institute of Advanced Industrial Science and Technology, Central 2, 1-1-1 Umezono, Tsukuba, Ibaraki 305-8568, Japan
| | - Xiao-Dong Gao
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China,
| | - Morihisa Fujita
- From the Key Laboratory of Carbohydrate Chemistry and Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, Jiangsu 214122, China,
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11
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Rother C, Gutmann A, Gudiminchi R, Weber H, Lepak A, Nidetzky B. Biochemical Characterization and Mechanistic Analysis of the Levoglucosan Kinase from Lipomyces starkeyi. Chembiochem 2018; 19:596-603. [DOI: 10.1002/cbic.201700587] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2017] [Indexed: 12/14/2022]
Affiliation(s)
- Christina Rother
- Institute of Biotechnology and Biochemical Engineering; Graz University of Technology, NAWI Graz; Petersgasse 12 8010 Graz Austria
| | - Alexander Gutmann
- Institute of Biotechnology and Biochemical Engineering; Graz University of Technology, NAWI Graz; Petersgasse 12 8010 Graz Austria
| | - Ramakrishna Gudiminchi
- Institute of Biotechnology and Biochemical Engineering; Graz University of Technology, NAWI Graz; Petersgasse 12 8010 Graz Austria
- Austrian Centre of Industrial Biotechnology; Petersgasse 14 8010 Graz Austria
| | - Hansjörg Weber
- Graz University of Technology, NAWI Graz; Stremayrgasse 9 8010 Graz Austria
| | - Alexander Lepak
- Institute of Biotechnology and Biochemical Engineering; Graz University of Technology, NAWI Graz; Petersgasse 12 8010 Graz Austria
| | - Bernd Nidetzky
- Institute of Biotechnology and Biochemical Engineering; Graz University of Technology, NAWI Graz; Petersgasse 12 8010 Graz Austria
- Austrian Centre of Industrial Biotechnology; Petersgasse 14 8010 Graz Austria
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12
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Males A, Raich L, Williams SJ, Rovira C, Davies GJ. Conformational Analysis of the Mannosidase Inhibitor Kifunensine: A Quantum Mechanical and Structural Approach. Chembiochem 2017; 18:1496-1501. [DOI: 10.1002/cbic.201700166] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2017] [Indexed: 11/10/2022]
Affiliation(s)
- Alexandra Males
- York Structural Biology Laboratory Department of Chemistry The University of York York YO10 5DD UK
| | - Lluís Raich
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) and Institut de Química Teòrica i Computacional (IQTCUB) Universitat de Barcelona Martí i Franquès 1 08028 Barcelona Spain
| | - Spencer J. Williams
- School of Chemistry Bio21 Molecular Science and Biotechnology Institute University of Melbourne Parkville VIC 3010 Australia
| | - Carme Rovira
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) and Institut de Química Teòrica i Computacional (IQTCUB) Universitat de Barcelona Martí i Franquès 1 08028 Barcelona Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA) Passeig Lluís Companys 23 08010 Barcelona Spain
| | - Gideon J. Davies
- York Structural Biology Laboratory Department of Chemistry The University of York York YO10 5DD UK
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13
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van Rijssel ER, Janssen APA, Males A, Davies GJ, van der Marel GA, Overkleeft HS, Codée JDC. Conformational Behaviour of Azasugars Based on Mannuronic Acid. Chembiochem 2017; 18:1297-1304. [DOI: 10.1002/cbic.201700080] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2017] [Indexed: 11/06/2022]
Affiliation(s)
- Erwin R. van Rijssel
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Antonius P. A. Janssen
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Alexandra Males
- York Structural Biology Laboratory; Department of Chemistry; The University of York; York YO10 5DD UK
| | - Gideon J. Davies
- York Structural Biology Laboratory; Department of Chemistry; The University of York; York YO10 5DD UK
| | | | - Herman S. Overkleeft
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
| | - Jeroen D. C. Codée
- Leiden Institute of Chemistry; Leiden University; Einsteinweg 55 2333 CC Leiden The Netherlands
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14
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Alonso-Gil S, Males A, Fernandes PZ, Williams SJ, Davies GJ, Rovira C. Computational Design of Experiment Unveils the Conformational Reaction Coordinate of GH125 α-Mannosidases. J Am Chem Soc 2017; 139:1085-1088. [DOI: 10.1021/jacs.6b11247] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Affiliation(s)
- Santiago Alonso-Gil
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain
| | - Alexandra Males
- York
Structural Biology Laboratory, Department of Chemistry, The University of York, YO10 5DD York, United Kingdom
| | - Pearl Z. Fernandes
- School
of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Spencer J. Williams
- School
of Chemistry and Bio21 Molecular Science and Biotechnology Institute, University of Melbourne, Melbourne, Victoria 3010, Australia
| | - Gideon J. Davies
- York
Structural Biology Laboratory, Department of Chemistry, The University of York, YO10 5DD York, United Kingdom
| | - Carme Rovira
- Departament de Química Inorgànica i Orgànica (Secció de Química Orgànica) & Institut de Química Teòrica i Computacional (IQTCUB), Universitat de Barcelona, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), 08010 Barcelona, Spain
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15
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Jin Y, Petricevic M, John A, Raich L, Jenkins H, Portela
De Souza L, Cuskin F, Gilbert H, Rovira C, Goddard-Borger ED, Williams SJ, Davies GJ. A β-Mannanase with a Lysozyme-like Fold and a Novel Molecular Catalytic Mechanism. ACS CENTRAL SCIENCE 2016; 2:896-903. [PMID: 28058278 PMCID: PMC5200933 DOI: 10.1021/acscentsci.6b00232] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/18/2016] [Indexed: 06/06/2023]
Abstract
The enzymatic cleavage of β-1,4-mannans is achieved by endo-β-1,4-mannanases, enzymes involved in germination of seeds and microbial hemicellulose degradation, and which have increasing industrial and consumer product applications. β-Mannanases occur in a range of families of the CAZy sequence-based glycoside hydrolase (GH) classification scheme including families 5, 26, and 113. In this work we reveal that β-mannanases of the newly described GH family 134 differ from other mannanase families in both their mechanism and tertiary structure. A representative GH family 134 endo-β-1,4-mannanase from a Streptomyces sp. displays a fold closely related to that of hen egg white lysozyme but acts with inversion of stereochemistry. A Michaelis complex with mannopentaose, and a product complex with mannotriose, reveal ligands with pyranose rings distorted in an unusual inverted chair conformation. Ab initio quantum mechanics/molecular mechanics metadynamics quantified the energetically accessible ring conformations and provided evidence in support of a 1C4 → 3H4‡ → 3S1 conformational itinerary along the reaction coordinate. This work, in concert with that on GH family 124 cellulases, reveals how the lysozyme fold can be co-opted to catalyze the hydrolysis of different polysaccharides in a mechanistically distinct manner.
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Affiliation(s)
- Yi Jin
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, U.K.
| | - Marija Petricevic
- School of Chemistry and Bio21 Molecular Science
and Biotechnology
Institute and Department of Medical Biology, University
of Melbourne, Parkville, Victoria 3010, Australia
| | - Alan John
- School of Chemistry and Bio21 Molecular Science
and Biotechnology
Institute and Department of Medical Biology, University
of Melbourne, Parkville, Victoria 3010, Australia
- ACRF
Chemical Biology Division, The Walter and
Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia
| | - Lluís Raich
- Departament
de Química Inorgànica i Orgànica (Secció
de Química Orgànica) & IQTCUB, Universitat de Barcelona, 08028 Barcelona, Spain
| | - Huw Jenkins
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, U.K.
| | - Leticia Portela
De Souza
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, U.K.
| | - Fiona Cuskin
- Institute
for Cell and Molecular Biosciences, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K.
| | - Harry
J. Gilbert
- Institute
for Cell and Molecular Biosciences, The Medical School, Newcastle University, Framlington Place, Newcastle upon Tyne NE2 4HH, U.K.
| | - Carme Rovira
- Departament
de Química Inorgànica i Orgànica (Secció
de Química Orgànica) & IQTCUB, Universitat de Barcelona, 08028 Barcelona, Spain
- Institució
Catalana de Recerca i Estudis Avançats (ICREA), 08020 Barcelona, Spain
| | - Ethan D. Goddard-Borger
- School of Chemistry and Bio21 Molecular Science
and Biotechnology
Institute and Department of Medical Biology, University
of Melbourne, Parkville, Victoria 3010, Australia
- ACRF
Chemical Biology Division, The Walter and
Eliza Hall Institute of Medical Research, Parkville, Victoria 3010, Australia
| | - Spencer J. Williams
- School of Chemistry and Bio21 Molecular Science
and Biotechnology
Institute and Department of Medical Biology, University
of Melbourne, Parkville, Victoria 3010, Australia
| | - Gideon J. Davies
- York
Structural Biology Laboratory, Department of Chemistry, University of York, Heslington, YO10 5DD, U.K.
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16
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Substrate recognition and catalysis by GH47 α-mannosidases involved in Asn-linked glycan maturation in the mammalian secretory pathway. Proc Natl Acad Sci U S A 2016; 113:E7890-E7899. [PMID: 27856750 DOI: 10.1073/pnas.1611213113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Maturation of Asn-linked oligosaccharides in the eukaryotic secretory pathway requires the trimming of nascent glycan chains to remove all glucose and several mannose residues before extension into complex-type structures on the cell surface and secreted glycoproteins. Multiple glycoside hydrolase family 47 (GH47) α-mannosidases, including endoplasmic reticulum (ER) α-mannosidase I (ERManI) and Golgi α-mannosidase IA (GMIA), are responsible for cleavage of terminal α1,2-linked mannose residues to produce uniquely trimmed oligomannose isomers that are necessary for ER glycoprotein quality control and glycan maturation. ERManI and GMIA have similar catalytic domain structures, but each enzyme cleaves distinct residues from tribranched oligomannose glycan substrates. The structural basis for branch-specific cleavage by ERManI and GMIA was explored by replacing an essential enzyme-bound Ca2+ ion with a lanthanum (La3+) ion. This ion swap led to enzyme inactivation while retaining high-affinity substrate interactions. Cocrystallization of La3+-bound enzymes with Man9GlcNAc2 substrate analogs revealed enzyme-substrate complexes with distinct modes of glycan branch insertion into the respective enzyme active-site clefts. Both enzymes had glycan interactions that extended across the entire glycan structure, but each enzyme engaged a different glycan branch and used different sets of glycan interactions. Additional mutagenesis and time-course studies of glycan cleavage probed the structural basis of enzyme specificity. The results provide insights into the enzyme catalytic mechanisms and reveal structural snapshots of the sequential glycan cleavage events. The data also indicate that full steric access to glycan substrates determines the efficiency of mannose-trimming reactions that control the conversion to complex-type structures in mammalian cells.
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17
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Quality control of glycoprotein folding and ERAD: the role of N-glycan handling, EDEM1 and OS-9. Histochem Cell Biol 2016; 147:269-284. [DOI: 10.1007/s00418-016-1513-9] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/20/2016] [Indexed: 02/03/2023]
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18
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Abstract
The enzyme-catalysed degradation of oligo and polysaccharides is of considerable interest in many fields ranging from the fundamental–understanding the intrinsic chemical beauty–through to the applied, including diverse practical applications in medicine and biotechnology. Carbohydrates are the most stereochemically-complex biopolymer, and myriad different natural polysaccharides have led to evolution of multifaceted enzyme consortia for their degradation. The glycosidic bonds that link sugar monomers are among the most chemically-stable, yet enzymatically-labile, bonds in the biosphere. That glycoside hydrolases can achieve a rate enhancement (kcat/kuncat) >1017-fold provides testament to their remarkable proficiency and the sophistication of their catalysis reaction mechanisms. The last two decades have seen significant advances in the discovery of new glycosidase sequences, sequence-based classification into families and clans, 3D structures and reaction mechanisms, providing new insights into enzymatic catalysis. New impetus to these studies has been provided by the challenges inherent in plant and microbial polysaccharide degradation, both in the context of environmentally-sustainable routes to foods and biofuels, and increasingly in human nutrition. Study of the reaction mechanism of glycoside hydrolases has also inspired the development of enzyme inhibitors, both as mechanistic probes and increasingly as therapeutic agents. We are on the cusp of a new era where we are learning how to dovetail powerful computational techniques with structural and kinetic data to provide an unprecedented view of conformational details of enzyme action.
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19
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Miura K, Hakamata W, Tanaka A, Hirano T, Nishio T. Discovery of human Golgi β-galactosidase with no identified glycosidase using a QMC substrate design platform for exo-glycosidase. Bioorg Med Chem 2016; 24:1369-75. [PMID: 26875935 DOI: 10.1016/j.bmc.2016.02.010] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2015] [Revised: 01/28/2016] [Accepted: 02/06/2016] [Indexed: 01/04/2023]
Abstract
Post-translational modifications (PTMs) of proteins play important roles in the physiology of eukaryotes. In the PTMs, non-reversible glycosylations are classified as N-glycosylations and O-glycosylations, and are catalyzed by various glycosidases and glycosyltransferases. However, β-glycosidases are not known to play a role in N- and O-glycan processing, although both glycans provide partial structures as substrates for β-galactosidase and β-N-acetylglucosaminidase in the Golgi apparatus of human cells. We explored human Golgi β-galactosidase using fluorescent substrates based on a quinone methide cleavage (QMC) substrate design platform that was previously developed to image exo-type glycosidases in living cells. As a result, we discovered a novel Golgi β-galactosidase in human cells. It is possible to predict a novel and important function in glycan processing of this β-galactosidase, because various β-galactosyl linkages in N- and O-glycans exist in Golgi apparatus. In addition, these results show that the QMC platform is excellent for imaging exo-type glycosidases.
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Affiliation(s)
- Kazuki Miura
- Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
| | - Wataru Hakamata
- Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan.
| | - Ayako Tanaka
- Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
| | - Takako Hirano
- Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
| | - Toshiyuki Nishio
- Department of Chemistry and Life Science, College of Bioresource Sciences, Nihon University, 1866 Kameino, Fujisawa-shi, Kanagawa 252-0880, Japan
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20
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Lin B, Su H, Ma G, Liu Y, Hou Q. Theoretical study of the hydrolysis mechanism of dihydrocoumarin catalyzed by serum paraoxonase 1 (PON1): different roles of Glu53 and His115 for catalysis. RSC Adv 2016. [DOI: 10.1039/c6ra09735a] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
In the PON1-catalyzed hydrolysis of dihydrocoumarin, Glu53 is necessary whereas His115 is not essential but can promote the activity.
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Affiliation(s)
- Beibei Lin
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
- China
| | - Hao Su
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
- China
| | - Guangcai Ma
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
- China
| | - Yongjun Liu
- School of Chemistry and Chemical Engineering
- Shandong University
- Jinan
- China
| | - Qianqian Hou
- Shandong Non-metallic Materials Institute
- Jinan
- China
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21
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Moreira NR, Cardoso C, Ribeiro AF, Ferreira C, Terra WR. Insect midgut α-mannosidases from family 38 and 47 with emphasis on those of Tenebrio molitor. INSECT BIOCHEMISTRY AND MOLECULAR BIOLOGY 2015; 67:94-104. [PMID: 26187253 DOI: 10.1016/j.ibmb.2015.07.012] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/02/2015] [Revised: 06/08/2015] [Accepted: 07/10/2015] [Indexed: 06/04/2023]
Abstract
α-Mannosidases are enzymes which remove non-reducing terminal residues from glycoconjugates. Data on both GH47 and GH38 (Golgi and lysosomal) enzymes are available. Data on insect midgut α-mannosidases acting in digestion are preliminary and do not include enzyme sequences. Tenebrio molitor midgut α-mannosidases were separated by chromatography into two activity peaks: a major (Man1) and a minor (Man2). An antibody generated against a synthetic peptide corresponding to a sequence of α-mannosidase fragment recognizes Man2 but not Man1. That fragment was later found to correspond to TmMan2 (GenBank access KP892646), showing that the cDNA coding for Man2 is actually TmMan2. TmMan2 codes for a mature α-mannosidase with 107.5 kDa. Purified Man2 originates after SDS-PAGE one band of about 72 kDa and another of 51 kDa, which sums 123 kDa, in agreement with gel filtration (123 kDa) data. These results suggest that Man2 is processed into peptides that remain noncovalently linked within the functional enzyme. The physical and kinetical properties of purified Man1 and Man2 are similar. They have a molecular mass of 123 kDa (gel filtration), pH optimum (5.6) and response to inhibitors like swainsonine (Man1 Ki, 68 nM; Man2 Ki, 63 nM) and deoxymannojirimycin (Man1 Ki, 0.12 mM; Man2 Ki, 0.15 mM). Their substrate specificities are a little different as Man2 hydrolyzes α-1,3 and α-1,6 bonds better than α-1,2, whereas the contrary is true for Man1. Thus, they pertain to Class II (GH38 α-mannosidases), that are catabolic α-mannosidases similar to lysosomal α-mannosidase. However, Man2, in contrast to true lysosomal α-mannosidase, is secreted (immunocytolocalization data) into the midgut contents. There, Man2 may participate in digestion of fungal cell walls, known to have α-mannosides in their outermost layer. The amount of family 38 α-mannosidase sequences found in the transcriptome (454 pyrosequencing) of the midgut of 9 insects pertaining to 5 orders is perhaps related to the diet of these organisms, as suggested by a large number of lysosomal α-mannosidase in the T. molitor midgut.
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Affiliation(s)
- Nathalia R Moreira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil
| | - Christiane Cardoso
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil
| | - Alberto F Ribeiro
- Departamento de Genética e Biologia Evolutiva, Instituto de Biociências, Universidade de São Paulo, C.P. 11461, 05513-970 São Paulo, Brazil
| | - Clelia Ferreira
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil
| | - Walter R Terra
- Departamento de Bioquímica, Instituto de Química, Universidade de São Paulo, C.P. 26077, 05513-970 São Paulo, Brazil.
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22
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Słomińska-Wojewódzka M, Sandvig K. The Role of Lectin-Carbohydrate Interactions in the Regulation of ER-Associated Protein Degradation. Molecules 2015; 20:9816-46. [PMID: 26023941 PMCID: PMC6272441 DOI: 10.3390/molecules20069816] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2015] [Revised: 05/20/2015] [Accepted: 05/21/2015] [Indexed: 01/08/2023] Open
Abstract
Proteins entering the secretory pathway are translocated across the endoplasmic reticulum (ER) membrane in an unfolded form. In the ER they are restricted to a quality control system that ensures correct folding or eventual degradation of improperly folded polypeptides. Mannose trimming of N-glycans on newly synthesized proteins plays an important role in the recognition and sorting of terminally misfolded glycoproteins for ER-associated protein degradation (ERAD). In this process misfolded proteins are retrotranslocated into the cytosol, polyubiquitinated, and eventually degraded by the proteasome. The mechanism by which misfolded glycoproteins are recognized and recruited to the degradation machinery has been extensively studied during last decade. In this review, we focus on ER degradation-enhancing α-mannosidase-like protein (EDEM) family proteins that seem to play a key role in the discrimination between proteins undergoing a folding process and terminally misfolded proteins directed for degradation. We describe interactions of EDEM proteins with other components of the ERAD machinery, as well as with various protein substrates. Carbohydrate-dependent interactions together with N-glycan-independent interactions seem to regulate the complex process of protein recognition and direction for proteosomal degradation.
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Affiliation(s)
| | - Kirsten Sandvig
- Department of Molecular Cell Biology, Institute for Cancer Research, Oslo University Hospital, The Norwegian Radium Hospital, 0379 Oslo, Norway.
- Centre for Cancer Biomedicine, Faculty of Medicine, University of Oslo, 0379 Oslo, Norway.
- Department of Biosciences, University of Oslo, 0316 Oslo, Norway.
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23
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Arnautova Y, Abagyan R, Totrov M. All-Atom Internal Coordinate Mechanics (ICM) Force Field for Hexopyranoses and Glycoproteins. J Chem Theory Comput 2015; 11:2167-2186. [PMID: 25999804 PMCID: PMC4431507 DOI: 10.1021/ct501138c] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2014] [Indexed: 01/24/2023]
Abstract
We present an extension of the all-atom internal-coordinate force field, ICMFF, that allows for simulation of heterogeneous systems including hexopyranose saccharides and glycan chains in addition to proteins. A library of standard glycan geometries containing α- and β-anomers of the most common hexapyranoses, i.e., d-galactose, d-glucose, d-mannose, d-xylose, l-fucose, N-acetylglucosamine, N-acetylgalactosamine, sialic, and glucuronic acids, is created based on the analysis of the saccharide structures reported in the Cambridge Structural Database. The new force field parameters include molecular electrostatic potential-derived partial atomic charges and the torsional parameters derived from quantum mechanical data for a collection of minimal molecular fragments and related molecules. The ϕ/ψ torsional parameters for different types of glycosidic linkages are developed using model compounds containing the key atoms in the full carbohydrates, i.e., glycosidic-linked tetrahydropyran-cyclohexane dimers. Target data for parameter optimization include two-dimensional energy surfaces corresponding to the ϕ/ψ glycosidic dihedral angles in the disaccharide analogues, as determined by quantum mechanical MP2/6-31G** single-point energies on HF/6-31G** optimized structures. To achieve better agreement with the observed geometries of glycosidic linkages, the bond angles at the O-linkage atoms are added to the internal variable set and the corresponding bond bending energy term is parametrized using quantum mechanical data. The resulting force field is validated on glycan chains of 1-12 residues from a set of high-resolution X-ray glycoprotein structures based on heavy atom root-mean-square deviations of the lowest-energy glycan conformations generated by the biased probability Monte Carlo (BPMC) molecular mechanics simulations from the native structures. The appropriate BPMC distributions for monosaccharide-monosaccharide and protein-glycan linkages are derived from the extensive analysis of conformational properties of glycoprotein structures reported in the Protein Data Bank. Use of the BPMC search leads to significant improvements in sampling efficiency for glycan simulations. Moreover, good agreement with the X-ray glycoprotein structures is achieved for all glycan chain lengths. Thus, average/median RMSDs are 0.81/0.68 Å for one-residue glycans and 1.32/1.47 Å for three-residue glycans. RMSD from the native structure for the lowest-energy conformation of the 12-residue glycan chain (PDB ID 3og2) is 1.53 Å. Additionally, results obtained for free short oligosaccharides using the new force field are in line with the available experimental data, i.e., the most populated conformations in solution are predicted to be the lowest energy ones. The newly developed parameters allow for the accurate modeling of linear and branched hexopyranose glycosides in heterogeneous systems.
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Affiliation(s)
- Yelena
A. Arnautova
- Molsoft
L.L.C., 11199 Sorrento
Valley Road, S209, San Diego, California 92121, United States
| | - Ruben Abagyan
- Skaggs
School of Pharmacy and Pharmaceutical Sciences, University of California San Diego, La Jolla, California 92093, United States
| | - Maxim Totrov
- Molsoft
L.L.C., 11199 Sorrento
Valley Road, S209, San Diego, California 92121, United States
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24
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Thompson AJ, Speciale G, Iglesias-Fernández J, Hakki Z, Belz T, Cartmell A, Spears RJ, Chandler E, Temple MJ, Stepper J, Gilbert HJ, Rovira C, Williams SJ, Davies GJ. Evidence for a Boat Conformation at the Transition State of GH76 α-1,6-Mannanases-Key Enzymes in Bacterial and Fungal Mannoprotein Metabolism. Angew Chem Int Ed Engl 2015. [DOI: 10.1002/ange.201410502] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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25
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Thompson AJ, Speciale G, Iglesias-Fernández J, Hakki Z, Belz T, Cartmell A, Spears RJ, Chandler E, Temple MJ, Stepper J, Gilbert HJ, Rovira C, Williams SJ, Davies GJ. Evidence for a boat conformation at the transition state of GH76 α-1,6-mannanases--key enzymes in bacterial and fungal mannoprotein metabolism. Angew Chem Int Ed Engl 2015; 54:5378-82. [PMID: 25772148 DOI: 10.1002/anie.201410502] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2014] [Revised: 01/29/2015] [Indexed: 01/21/2023]
Abstract
α-Mannosidases and α-mannanases have attracted attention for the insight they provide into nucleophilic substitution at the hindered anomeric center of α-mannosides, and the potential of mannosidase inhibitors as cellular probes and therapeutic agents. We report the conformational itinerary of the family GH76 α-mannanases studied through structural analysis of the Michaelis complex and synthesis and evaluation of novel aza/imino sugar inhibitors. A Michaelis complex in an (O) S2 conformation, coupled with distortion of an azasugar in an inhibitor complex to a high energy B2,5 conformation are rationalized through ab initio QM/MM metadynamics that show how the enzyme surface restricts the conformational landscape of the substrate, rendering the B2,5 conformation the most energetically stable on-enzyme. We conclude that GH76 enzymes perform catalysis using an itinerary that passes through (O) S2 and B2,5 (≠) conformations, information that should inspire the development of new antifungal agents.
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Affiliation(s)
- Andrew J Thompson
- Department of Chemistry, University of York, Heslington, York, YO10 5DD (UK)
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26
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Hoffjan S, Epplen JT, Reis A, Abou Jamra R. MAN1B1 Mutation Leads to a Recognizable Phenotype: A Case Report and Future Prospects. Mol Syndromol 2015; 6:58-62. [PMID: 26279649 DOI: 10.1159/000371399] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/21/2014] [Indexed: 01/23/2023] Open
Abstract
Intellectual disability (ID) is one of the most common reasons for referral to genetic counseling. Nevertheless, in over 50% of the cases no diagnosis can be made. Here, we present how exome sequencing in combination with medical genetics evaluation led to the identification of a known pathogenic homozygous mutation in MAN1B1 in a consanguineous Turkish family. The phenotype comprised mild ID, truncal obesity and facial dysmorphism, comparable to that of the patients in the 3 recent publications on mutations in this gene. Clinically, the majority of patients in the literature showed congenital disorder of glycosylation syndrome type 2. In this study, we summarize the current knowledge about MAN1B1 mutations from the literature as well as databases and suggest that exome sequencing should be implemented in a larger scale in routine diagnostics, since autosomal recessive ID has proven to be extremely heterogeneous. Even syndromic patterns may only become recognizable retrospectively.
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Affiliation(s)
- Sabine Hoffjan
- Department of Human Genetics, Ruhr-University, Bochum, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Jörg T Epplen
- Department of Human Genetics, Ruhr-University, Bochum, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - André Reis
- Institute of Human Genetics, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
| | - Rami Abou Jamra
- Institute of Human Genetics, Friedrich-Alexander-University, Erlangen-Nuremberg, Germany
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27
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Sokołowska I, Piłka ES, Sandvig K, Węgrzyn G, Słomińska-Wojewódzka M. Hydrophobicity of protein determinants influences the recognition of substrates by EDEM1 and EDEM2 in human cells. BMC Cell Biol 2015; 16:1. [PMID: 25655076 PMCID: PMC4340280 DOI: 10.1186/s12860-015-0047-7] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2014] [Accepted: 01/05/2015] [Indexed: 11/22/2022] Open
Abstract
Background EDEM1 and EDEM2 are crucial regulators of the endoplasmic reticulum (ER)-associated degradation (ERAD) that extracts misfolded glycoproteins from the calnexin chaperone system. The degradation of ERAD substrates involves mannose trimming of N-linked glycans; however the precise mechanism of substrate recognition and sorting to the ERAD pathway is still poorly understood. It has previously been demonstrated that EDEM1 and EDEM2 binding does not require the trimming of substrate glycans or even ERAD substrate glycosylation, thus suggesting that both chaperones probably recognize misfolded regions of aberrant proteins. Results In this work, we focused on the substrate recognition by EDEM1 and EDEM2, asking whether hydrophobicity of protein determinants might be important for these interactions in human cells. In the study we used ricin, a protein toxin that utilizes the ERAD pathway in its retrotranslocation from the ER to the cytosol, and a model misfolded protein, the pancreatic isoform of human β-secretase, BACE457. Mutations in the hydrophobic regions of these proteins allowed us to obtain mutated forms with increased and decreased hydrophobicity. Conclusions Our data provide the first evidence that recognition of ERAD substrates by EDEM1 and EDEM2 might be determined by a sufficiently high hydrophobicity of protein determinants. Moreover, EDEM proteins can bind hydrophobic transmembrane regions of misfolded ERAD substrates. These data contribute to the general understanding of the regulation of ERAD in mammalian cells. Electronic supplementary material The online version of this article (doi:10.1186/s12860-015-0047-7) contains supplementary material, which is available to authorized users.
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Emerging structural insights into glycoprotein quality control coupled with N-glycan processing in the endoplasmic reticulum. Molecules 2015; 20:2475-91. [PMID: 25647580 PMCID: PMC6272264 DOI: 10.3390/molecules20022475] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2014] [Revised: 01/04/2015] [Accepted: 01/22/2015] [Indexed: 01/22/2023] Open
Abstract
In the endoplasmic reticulum (ER), the sugar chain is initially introduced onto newly synthesized proteins as a triantennary tetradecasaccharide (Glc3Man9GlcNAc2). The attached oligosaccharide chain is subjected to stepwise trimming by the actions of specific glucosidases and mannosidases. In these processes, the transiently expressed N-glycans, as processing intermediates, function as signals for the determination of glycoprotein fates, i.e., folding, transport, or degradation through interactions of a series of intracellular lectins. The monoglucosylated glycoforms are hallmarks of incompletely folded states of glycoproteins in this system, whereas the outer mannose trimming leads to ER-associated glycoprotein degradation. This review outlines the recently emerging evidence regarding the molecular and structural basis of this glycoprotein quality control system, which is regulated through dynamic interplay among intracellular lectins, glycosidases, and glycosyltransferase. Structural snapshots of carbohydrate-lectin interactions have been provided at the atomic level using X-ray crystallographic analyses. Conformational ensembles of uncomplexed triantennary high-mannose-type oligosaccharides have been characterized in a quantitative manner using molecular dynamics simulation in conjunction with nuclear magnetic resonance spectroscopy. These complementary views provide new insights into glycoprotein recognition in quality control coupled with N-glycan processing.
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29
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'Click chemistry' synthesis of 1-(α-D-mannopyranosyl)-1,2,3-triazoles for inhibition of α-mannosidases. Carbohydr Res 2015; 406:34-40. [PMID: 25658064 DOI: 10.1016/j.carres.2015.01.004] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2014] [Revised: 01/09/2015] [Accepted: 01/11/2015] [Indexed: 12/14/2022]
Abstract
Three new triazole conjugates derived from d-mannose were synthesized and assayed in in vitro assays to investigate their ability to inhibit α-mannosidase enzymes from the glycoside hydrolase (GH) families 38 and 47. The triazole conjugates were more selective for a GH47 α-mannosidase (Aspergillus saitoi α1,2-mannosidase), showing inhibition at the micromolar level (IC50 values of 50-250 μM), and less potent towards GH38 mannosidases (IC50 values in the range of 0.5-6 mM towards jack bean α-mannosidase or Drosophila melanogaster lysosomal and Golgi α-mannosidases). The highest selectivity ratio [IC50(GH38)/IC50(GH47)] of 100 was exhibited by the phenyltriazole conjugate. To understand structure-activity properties of synthesized compounds, 3-D complexes of inhibitors with α-mannosidases were built using molecular docking calculations.
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30
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Hakamata W, Miura K, Hirano T, Nishio T. Identification of a novel glycan processing enzyme with exo-acting β-allosidase activity in the Golgi apparatus using a new platform for the synthesis of fluorescent substrates. Bioorg Med Chem 2015; 23:73-9. [DOI: 10.1016/j.bmc.2014.11.023] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 11/13/2014] [Accepted: 11/14/2014] [Indexed: 10/24/2022]
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31
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Parihar VS, Pawar NJ, Ghosh S, Chopade B, Kumbhar N, Dhavale DD. Diazaspiro-iminosugars and polyhydroxylated spiro-bislactams: synthesis, glycosidase inhibition and molecular docking studies. RSC Adv 2015. [DOI: 10.1039/c5ra09584k] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022] Open
Abstract
Synthesis of a new class of iminosugars 1–4 has been reported.
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Affiliation(s)
- Vijay Singh Parihar
- Department of Chemistry
- Garware Research Centre
- Savitribai Phule Pune University (Formerly University of Pune)
- Pune-411 007
- India
| | - Nitin J. Pawar
- Department of Chemistry
- Garware Research Centre
- Savitribai Phule Pune University (Formerly University of Pune)
- Pune-411 007
- India
| | - Sougata Ghosh
- Department of Microbiology
- Savitribai Phule Pune University
- Pune-411 007
- India
| | - Balu Chopade
- Department of Microbiology
- Savitribai Phule Pune University
- Pune-411 007
- India
| | - Navanath Kumbhar
- Department of Chemistry
- Garware Research Centre
- Savitribai Phule Pune University (Formerly University of Pune)
- Pune-411 007
- India
| | - Dilip D. Dhavale
- Department of Chemistry
- Garware Research Centre
- Savitribai Phule Pune University (Formerly University of Pune)
- Pune-411 007
- India
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32
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Makeneni S, Foley BL, Woods RJ. BFMP: a method for discretizing and visualizing pyranose conformations. J Chem Inf Model 2014; 54:2744-50. [PMID: 25289680 PMCID: PMC4210171 DOI: 10.1021/ci500325b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
We report a new classification method for pyranose ring conformations called Best-fit, Four-Membered Plane (BFMP), which describes pyranose ring conformations based on reference planes defined by four atoms. The method is able to characterize all asymmetrical and symmetrical shapes of a pyran ring, is readily automated, easy to interpret, and maps trivially to IUPAC definitions. It also provides a qualitative measurement of the distortion of the ring. Example applications include the analysis of data from crystal structures and molecular dynamics simulations.
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Affiliation(s)
- Spandana Makeneni
- Complex Carbohydrate Research Center, University of Georgia , 315 Riverbend Road, Athens, Georgia 30602, United States
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33
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Tang HY, Huang CH, Zhuang YH, Christianson JC, Chen X. EDEM2 and OS-9 are required for ER-associated degradation of non-glycosylated sonic hedgehog. PLoS One 2014; 9:e92164. [PMID: 24910992 PMCID: PMC4049591 DOI: 10.1371/journal.pone.0092164] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 02/19/2014] [Indexed: 11/18/2022] Open
Abstract
Misfolded proteins of the endoplasmic reticulum (ER) are eliminated by the ER-associated degradation (ERAD) in eukaryotes. In S. cerevisiae, ER-resident lectins mediate substrate recognition through bipartite signals consisting of an unfolded local structure and the adjacent glycan. Trimming of the glycan is essential for the directional delivery of the substrates. Whether a similar recognition and delivery mechanism exists in mammalian cells is unknown. In this study, we systematically study the function and substrate specificity of known mammalian ER lectins, including EDEM1/2/3, OS-9 and XTP-3B using the recently identified ERAD substrate sonic hedgehog (SHH), a soluble protein carrying a single N-glycan, as well as its nonglycosylated mutant N278A. Efficient ERAD of N278A requires the core processing complex of HRD1, SEL1L and p97, similar to the glycosylated SHH. While EDEM2 was required for ERAD of both glycosylated and non-glycosylated SHHs, EDEM3 was only necessary for glycosylated SHH and EDEM1 was dispensable for both. Degradation of SHH and N278A also required OS-9, but not the related lectin XTP3-B. Robust interaction of both EDEM2 and OS-9 with a non-glycosylated SHH variant indicates that the misfolded polypeptide backbone, rather than a glycan signature, functions as the predominant signal for recognition for ERAD. Notably, SHH-N278A is the first nonglycosylated substrate to require EDEM2 for recognition and targeting for ERAD. EDEM2 also interacts with calnexin and SEL1L, suggesting a potential avenue by which misfolded glycoproteins may be shunted towards SEL1L and ERAD rather than being released into the secretory pathway. Thus, ER lectins participate in the recognition and delivery of misfolded ER substrates differently in mammals, with an underlying mechanism distinct from that of S. cerevisiae.
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Affiliation(s)
- Hsiang-Yun Tang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Chunan town, Miaoli, Taiwan, ROC
| | - Chih-Hsiang Huang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Chunan town, Miaoli, Taiwan, ROC
| | - Ya-Han Zhuang
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Chunan town, Miaoli, Taiwan, ROC
| | - John C. Christianson
- Ludwig Institute for Cancer Research, University of Oxford, ORCRB, Headington, Oxford, United Kingdom
| | - Xin Chen
- Institute of Biotechnology and Pharmaceutical Research, National Health Research Institutes, Chunan town, Miaoli, Taiwan, ROC
- Graduate Institute of Basic Medical Science, China Medical University, Taichung, Taiwan, ROC
- * E-mail:
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34
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Iannotti MJ, Figard L, Sokac AM, Sifers RN. A Golgi-localized mannosidase (MAN1B1) plays a non-enzymatic gatekeeper role in protein biosynthetic quality control. J Biol Chem 2014; 289:11844-11858. [PMID: 24627495 DOI: 10.1074/jbc.m114.552091] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022] Open
Abstract
Conformation-based disorders are manifested at the level of protein structure, necessitating an accurate understanding of how misfolded proteins are processed by the cellular proteostasis network. Asparagine-linked glycosylation plays important roles for protein quality control within the secretory pathway. The suspected role for the MAN1B1 gene product MAN1B1, also known as ER mannosidase I, is to function within the ER similar to the yeast ortholog Mns1p, which removes a terminal mannose unit to initiate a glycan-based ER-associated degradation (ERAD) signal. However, we recently discovered that MAN1B1 localizes to the Golgi complex in human cells and uncovered its participation in ERAD substrate retention, retrieval to the ER, and subsequent degradation from this organelle. The objective of the current study was to further characterize the contribution of MAN1B1 as part of a Golgi-based quality control network. Multiple lines of experimental evidence support a model in which neither the mannosidase activity nor catalytic domain is essential for the retention or degradation of the misfolded ERAD substrate Null Hong Kong. Instead, a highly conserved, vertebrate-specific non-enzymatic decapeptide sequence in the luminal stem domain plays a significant role in controlling the fate of overexpressed Null Hong Kong. Together, these findings define a new functional paradigm in which Golgi-localized MAN1B1 can play a mannosidase-independent gatekeeper role in the proteostasis network of higher eukaryotes.
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Affiliation(s)
- Michael J Iannotti
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030
| | - Lauren Figard
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Anna M Sokac
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030
| | - Richard N Sifers
- Interdepartmental Program in Cell and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030; Department of Pathology and Immunology, Baylor College of Medicine, Houston, Texas 77030; Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas 77030; Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas 77030.
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35
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Ferris SP, Kodali VK, Kaufman RJ. Glycoprotein folding and quality-control mechanisms in protein-folding diseases. Dis Model Mech 2014; 7:331-41. [PMID: 24609034 PMCID: PMC3944493 DOI: 10.1242/dmm.014589] [Citation(s) in RCA: 64] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2013] [Accepted: 01/14/2014] [Indexed: 12/31/2022] Open
Abstract
Biosynthesis of proteins--from translation to folding to export--encompasses a complex set of events that are exquisitely regulated and scrutinized to ensure the functional quality of the end products. Cells have evolved to capitalize on multiple post-translational modifications in addition to primary structure to indicate the folding status of nascent polypeptides to the chaperones and other proteins that assist in their folding and export. These modifications can also, in the case of irreversibly misfolded candidates, signal the need for dislocation and degradation. The current Review focuses on the glycoprotein quality-control (GQC) system that utilizes protein N-glycosylation and N-glycan trimming to direct nascent glycopolypeptides through the folding, export and dislocation pathways in the endoplasmic reticulum (ER). A diverse set of pathological conditions rooted in defective as well as over-vigilant ER quality-control systems have been identified, underlining its importance in human health and disease. We describe the GQC pathways and highlight disease and animal models that have been instrumental in clarifying our current understanding of these processes.
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Affiliation(s)
- Sean P. Ferris
- Department of Biological Chemistry and Medical Scientist Training Program, University of Michigan, Ann Arbor, MI 48109, USA
| | - Vamsi K. Kodali
- Center for Neuroscience, Aging and Stem Cell Research, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
| | - Randal J. Kaufman
- Center for Neuroscience, Aging and Stem Cell Research, Sanford-Burnham Medical Research Institute, 10901 N. Torrey Pines Road, La Jolla, CA 92037, USA
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36
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Van Scherpenzeel M, Timal S, Rymen D, Hoischen A, Wuhrer M, Hipgrave-Ederveen A, Grunewald S, Peanne R, Saada A, Edvardson S, Grønborg S, Ruijter G, Kattentidt-Mouravieva A, Brum JM, Freckmann ML, Tomkins S, Jalan A, Prochazkova D, Ondruskova N, Hansikova H, Willemsen MA, Hensbergen PJ, Matthijs G, Wevers RA, Veltman JA, Morava E, Lefeber DJ. Diagnostic serum glycosylation profile in patients with intellectual disability as a result of MAN1B1 deficiency. ACTA ACUST UNITED AC 2014; 137:1030-8. [PMID: 24566669 DOI: 10.1093/brain/awu019] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Congenital disorders of glycosylation comprise a group of genetic defects with a high frequency of intellectual disability, caused by deficient glycosylation of proteins and lipids. The molecular basis of the majority of the congenital disorders of glycosylation type I subtypes, localized in the cytosol and endoplasmic reticulum, has been solved. However, elucidation of causative genes for defective Golgi glycosylation (congenital disorders of glycosylation type II) remains challenging because of a lack of sufficiently specific diagnostic serum methods. In a single patient with intellectual disability, whole-exome sequencing revealed MAN1B1 as congenital disorder of glycosylation type II candidate gene. A novel mass spectrometry method was applied for high-resolution glycoprofiling of intact plasma transferrin. A highly characteristic glycosylation signature was observed with hybrid type N-glycans, in agreement with deficient mannosidase activity. The speed and robustness of the method allowed subsequent screening in a cohort of 100 patients with congenital disorder of glycosylation type II, which revealed the characteristic glycosylation profile of MAN1B1-congenital disorder of glycosylation in 11 additional patients. Abnormal hybrid type N-glycans were also observed in the glycoprofiles of total serum proteins, of enriched immunoglobulins and of alpha1-antitrypsin in variable amounts. Sanger sequencing revealed MAN1B1 mutations in all patients, including severe truncating mutations and amino acid substitutions in the alpha-mannosidase catalytic site. Clinically, this group of patients was characterized by intellectual disability and delayed motor and speech development. In addition, variable dysmorphic features were noted, with truncal obesity and macrocephaly in ∼65% of patients. In summary, MAN1B1 deficiency appeared to be a frequent cause in our cohort of patients with unsolved congenital disorder of glycosylation type II. Our method for analysis of intact transferrin provides a rapid test to detect MAN1B1-deficient patients within congenital disorder of glycosylation type II cohorts and can be used as efficient diagnostic method to identify MAN1B1-deficient patients in intellectual disability cohorts. In addition, it provides a functional confirmation of MAN1B1 mutations as identified by next-generation sequencing in individuals with intellectual disability.
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Affiliation(s)
- Monique Van Scherpenzeel
- 1 Laboratory of Genetic, Endocrine and Metabolic Diseases, Radboud University Medical Centre, Nijmegen, The Netherlands
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37
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Fujimoto Z, Tateno H, Hirabayashi J. Lectin structures: classification based on the 3-D structures. Methods Mol Biol 2014; 1200:579-606. [PMID: 25117265 DOI: 10.1007/978-1-4939-1292-6_46] [Citation(s) in RCA: 35] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022]
Abstract
Recent progress in structural biology has elucidated the three-dimensional structures and carbohydrate-binding mechanisms of most lectin families. Lectins are classified into 48 families based on their three-dimensional structures. A ribbon drawing gallery of the crystal and solution structures of representative lectins or lectin-like proteins is appended and may help to convey the diversity of lectin families, the similarity and differences between lectin families, as well as the carbohydrate-binding architectures of lectins.
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Affiliation(s)
- Zui Fujimoto
- Biomolecular Research Unit, National Institute of Agrobiological Sciences, 2-1-2 Kannondai, Tsukuba, 305-8602, Japan,
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38
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Pan S, Cheng X, Sifers RN. Golgi-situated endoplasmic reticulum α-1, 2-mannosidase contributes to the retrieval of ERAD substrates through a direct interaction with γ-COP. Mol Biol Cell 2013; 24:1111-21. [PMID: 23427261 PMCID: PMC3623633 DOI: 10.1091/mbc.e12-12-0886] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/03/2022] Open
Abstract
Endoplasmic reticulum (ER) α-1, 2-mannosidase and γ-COP contribute to a Golgi-based quality control module that facilitates the retrieval of captured ER-associated protein degradation substrates back to the ER. Endoplasmic reticulum (ER) α-1, 2-mannosidase (ERManI) contributes to ER-associated protein degradation (ERAD) by initiating the formation of degradation signals on misfolded N-linked glycoproteins. Despite its inferred intracellular location, we recently discovered that the mammalian homologue is actually localized to the Golgi complex. In the present study, the functional role of Golgi-situated ERManI was investigated. Mass spectrometry analysis and coimmunoprecipitation (co-IP) identified a direct interaction between ERManI and γ-COP, the gamma subunit of coat protein complex I (COPI) that is responsible for Golgi-to-ER retrograde cargo transport. The functional relationship was validated by the requirement of both ERManI and γ-COP to support efficient intracellular clearance of the classical ERAD substrate, null Hong Kong (NHK). In addition, site-directed mutagenesis of suspected γ-COP–binding motifs in the cytoplasmic tail of ERManI was sufficient to disrupt the physical interaction and ablate NHK degradation. Moreover, a physical interaction between NHK, ERManI, and γ-COP was identified by co-IP and Western blotting. RNA interference–mediated knockdown of γ-COP enhanced the association between ERManI and NHK, while diminishing the efficiency of ERAD. Based on these findings, a model is proposed in which ERManI and γ-COP contribute to a Golgi-based quality control module that facilitates the retrieval of captured ERAD substrates back to the ER.
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Affiliation(s)
- Shujuan Pan
- Department of Pathology, Baylor College of Medicine, Houston, TX 77030, USA
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39
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Walvoort MTC, van der Marel GA, Overkleeft HS, Codée JDC. On the reactivity and selectivity of donor glycosides in glycochemistry and glycobiology: trapped covalent intermediates. Chem Sci 2013. [DOI: 10.1039/c2sc21610h] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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40
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Virtual screening and QSAR study of some pyrrolidine derivatives as α-mannosidase inhibitors for binding feature analysis. Bioorg Med Chem 2012; 20:6945-59. [DOI: 10.1016/j.bmc.2012.10.011] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Accepted: 10/14/2012] [Indexed: 11/22/2022]
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41
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Thompson AJ, Dabin J, Iglesias-Fernández J, Ardèvol A, Dinev Z, Williams SJ, Bande O, Siriwardena A, Moreland C, Hu TC, Smith DK, Gilbert HJ, Rovira C, Davies GJ. The Reaction Coordinate of a Bacterial GH47 α-Mannosidase: A Combined Quantum Mechanical and Structural Approach. Angew Chem Int Ed Engl 2012; 51:10997-1001. [DOI: 10.1002/anie.201205338] [Citation(s) in RCA: 50] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Indexed: 11/10/2022]
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42
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Thompson AJ, Dabin J, Iglesias-Fernández J, Ardèvol A, Dinev Z, Williams SJ, Bande O, Siriwardena A, Moreland C, Hu TC, Smith DK, Gilbert HJ, Rovira C, Davies GJ. The Reaction Coordinate of a Bacterial GH47 α-Mannosidase: A Combined Quantum Mechanical and Structural Approach. Angew Chem Int Ed Engl 2012. [DOI: 10.1002/ange.201205338] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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43
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Marin MB, Ghenea S, Spiridon LN, Chiritoiu GN, Petrescu AJ, Petrescu SM. Tyrosinase degradation is prevented when EDEM1 lacks the intrinsically disordered region. PLoS One 2012; 7:e42998. [PMID: 22905195 PMCID: PMC3414498 DOI: 10.1371/journal.pone.0042998] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2012] [Accepted: 07/16/2012] [Indexed: 01/08/2023] Open
Abstract
EDEM1 is a mannosidase-like protein that recruits misfolded glycoproteins from the calnexin/calreticulin folding cycle to downstream endoplasmic reticulum associated degradation (ERAD) pathway. Here, we investigate the role of EDEM1 in the processing of tyrosinase, a tumour antigen overexpressed in melanoma cells. First, we analyzed and modeled EDEM1 major domains. The homology model raised on the crystal structures of human and Saccharomyces cerevisiae ER class I α1,2-mannosidases reveals that the major mannosidase domain located between aminoacids 121-598 fits with high accuracy. We have further identified an N-terminal region located between aminoacids 40-119, predicted to be intrinsically disordered (ID) and susceptible to adopt multiple conformations, hence facilitating protein-protein interactions. To investigate these two domains we have constructed an EDEM1 deletion mutant lacking the ID region and a triple mutant disrupting the glycan-binding domain and analyzed their association with tyrosinase. Tyrosinase is a glycoprotein partly degraded endogenously by ERAD and the ubiquitin proteasomal system. We found that the degradation of wild type and misfolded tyrosinase was enhanced when EDEM1 was overexpressed. Glycosylated and non-glycosylated mutants co-immunoprecipitated with EDEM1 even in the absence of its intact mannosidase-like domain, but not when the ID region was deleted. In contrast, calnexin and SEL 1L associated with the deletion mutant. Our data suggest that the ID region identified in the N-terminal end of EDEM1 is involved in the binding of glycosylated and non-glycosylated misfolded proteins. Accelerating tyrosinase degradation by EDEM1 overexpression may lead to an efficient antigen presentation and enhanced elimination of melanoma cells.
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Affiliation(s)
- Marioara B. Marin
- Department of Molecular Cell Biology, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
| | - Simona Ghenea
- Department of Molecular Cell Biology, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
| | - Laurentiu N. Spiridon
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
| | - Gabriela N. Chiritoiu
- Department of Molecular Cell Biology, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
| | - Andrei-Jose Petrescu
- Department of Bioinformatics and Structural Biochemistry, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
- * E-mail: (SMP); (AJP)
| | - Stefana-Maria Petrescu
- Department of Molecular Cell Biology, Institute of Biochemistry of Romanian Academy, Bucharest, Romania
- * E-mail: (SMP); (AJP)
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44
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Davies GJ, Planas A, Rovira C. Conformational analyses of the reaction coordinate of glycosidases. Acc Chem Res 2012; 45:308-16. [PMID: 21923088 DOI: 10.1021/ar2001765] [Citation(s) in RCA: 184] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The enzymatic hydrolysis of the glycosidic bond is catalyzed by diverse enzymes generically termed glycoside hydrolases (hereafter GHs) or glycosidases. The many sequence-based families of glycosidases have served as a rich hunting ground for enzymologists for years. Not only are these enzymes of fundamental interest, providing paradigms for enzymatic catalysis that extend beyond the bounds of carbohydrate chemistry, but the enzymes themselves play myriad essential roles in diverse biological processes. The wide utility of glycosidases, from their industrial harnessing in the hydrolysis of plant biomass to their roles in human physiology and disease, has engendered a large scientific constituency with an interest in glycosidase chemistry. A fascinating thread of this research, and one with major impact on the design of enzyme inhibitors, is the conformational analysis of reaction pathways within the diverse families. These GH families provide a large pallet of enzymes with which chemists have attempted to depict the conformational landscape of glycosidase action. In this Account, we review three-dimensional insight into the conformational changes directed by glycosidases, primarily from structural observations of the stable enzyme-ligand species adjacent to the transition state (or states) and of enzyme-inhibitor complexes. We further show how recent computational advances dovetail with structural insight to provide a quantum mechanical basis for glycosidase action. The glycosidase-mediated hydrolysis of the acetal or ketal bond in a glycoside may occur with either inversion or retention of the configuration of the anomeric carbon. Inversion involves a single step and transition state, whereas retention, often referred to as the double displacement, is a two-step process with two transition states. The single transition state for the inverting enzymes and the two transition states (those flanking the covalent intermediate) in the double displacement have been shown to have substantial oxocarbenium ion character. The dissociative nature of these transition states results in significant relative positive charge accumulation on the pyranose ring. The delocalization of lone-pair electrons from the ring oxygen that stabilizes the cationic transition state implies that at, or close to, the transition states the pyranose will be distorted away from its lowest energy conformation to one that favors orbital overlap. Over the preceding decade, research has highlighted the harnessing of noncovalent interactions to aid this distortion of the sugar substrates from their lowest energy chair conformation to a variety of different boat, skew boat, and half-chair forms, each of which favors catalysis with a given enzyme and substrate. Crystallographic observation of stable species that flank the transition state (or states), of both retaining and inverting glycosidases, has allowed a description of their conformational itineraries, illustrating how enzymes facilitate the "electrophilic migration" of the anomeric center along the reaction coordinate. The blossoming of computational approaches, such as ab initio metadynamics, has underscored the quantum mechanical basis for glycoside hydrolysis. Conformational analyses highlight not only the itineraries used by enzymes, enabling their inhibition, but are also reflected in the nonenzymatic synthesis of glycosides, wherein chemists mimic strategies found in nature.
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Affiliation(s)
- Gideon J. Davies
- Structural Biology Laboratory, Department of Chemistry, The University of York, YO10 5DD, United Kingdom
| | - Antoni Planas
- Laboratory of Biochemistry, Institut Químic de Sarrià, Universitat Ramon Llull, c/Via Augusta 390, 08017 Barcelona, Spain
| | - Carme Rovira
- Computer Simulation & Modeling and Institut de Química Teòrica i Computacional (IQTCUB), Parc Científic de Barcelona, Baldiri Reixac 4, 08028 Barcelona, Spain
- Institució Catalana de Recerca i Estudis Avançats (ICREA), Passeig Lluís Companys 23, 08018 Barcelona, Spain
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45
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Aikawa JI, Matsuo I, Ito Y. In vitro mannose trimming property of human ER α-1,2 mannosidase I. Glycoconj J 2011; 29:35-45. [PMID: 22160784 DOI: 10.1007/s10719-011-9362-1] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2011] [Revised: 11/13/2011] [Accepted: 11/16/2011] [Indexed: 12/31/2022]
Abstract
Endoplasmic reticulum α-1,2 mannosidase I (ERManI) is an enzyme, which removes α(1-2) linked mannoses from asparagine-linked oligosaccharides on glycoproteins in the endoplasmic reticulum (ER). ERManI preferentially removes one α(1-2) linked mannose from B-chain of Man(9)GlcNAc(2). When glycoproteins fail to achieve properly folding, increased removal of α(1-2) linked mannoses on their oligosaccharides is induced and leads them to be disposed and degraded by ER-associated degradation pathway. However, it is still inconclusive whether accelerated removal of α(1-2) linked mannoses on those glycoproteins is catalyzed by the α-1,2 mannosidase I, proteins similar to mannosidase I [e.g. ER degradation-enhancing α-1,2 mannosidase-like protein (EDEM)], or both of them. Therefore, to approach this issue, we have investigated its in vitro activities using various oligosaccharides and glycoproteins as substrates. A recombinant form of human ERManI (hERManI) was prepared by using Escherichia coli. First, the enzyme generated Man(6)GlcNAc(2)-PA and Man(5)GlcNAc(2)-PA from 100 μM Man(9)GlcNAc(2)-PA after a one-hour reaction. Second, we have exposed bovine thyroglobulin and soybean agglutinin to denaturing conditions, e.g. 8 M urea, and used those glycoproteins as substrates. Sugar moieties were released from the reactant by PNGase F and their structures and amounts were elucidated by HPLC analysis. Intriguingly, the enzyme was shown to remove mannoses from bovine thyroglobulin and soybean agglutinin to larger extents when they were exposed to a denaturant. Therefore, our results suggested that hERManI could recognize tertiary and/or quaternary structures of glycoproteins and remove more α-1,2 linked mannoses from misfolded glycoproteins in living cells.
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Affiliation(s)
- Jun-ichi Aikawa
- RIKEN Advanced Science Institute, Hirosawa, Wako, Saitama, Japan.
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Rafiq MA, Kuss AW, Puettmann L, Noor A, Ramiah A, Ali G, Hu H, Kerio NA, Xiang Y, Garshasbi M, Khan MA, Ishak GE, Weksberg R, Ullmann R, Tzschach A, Kahrizi K, Mahmood K, Naeem F, Ayub M, Moremen KW, Vincent JB, Ropers HH, Ansar M, Najmabadi H. Mutations in the alpha 1,2-mannosidase gene, MAN1B1, cause autosomal-recessive intellectual disability. Am J Hum Genet 2011; 89:176-82. [PMID: 21763484 DOI: 10.1016/j.ajhg.2011.06.006] [Citation(s) in RCA: 63] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/09/2011] [Revised: 05/19/2011] [Accepted: 06/07/2011] [Indexed: 11/15/2022] Open
Abstract
We have used genome-wide genotyping to identify an overlapping homozygosity-by-descent locus on chromosome 9q34.3 (MRT15) in four consanguineous families affected by nonsyndromic autosomal-recessive intellectual disability (NS-ARID) and one in which the patients show additional clinical features. Four of the families are from Pakistan, and one is from Iran. Using a combination of next-generation sequencing and Sanger sequencing, we have identified mutations in the gene MAN1B1, encoding a mannosyl oligosaccharide, alpha 1,2-mannosidase. In one Pakistani family, MR43, a homozygous nonsense mutation (RefSeq number NM_016219.3: c.1418G>A [p.Trp473*]), segregated with intellectual disability and additional dysmorphic features. We also identified the missense mutation c. 1189G>A (p.Glu397Lys; RefSeq number NM_016219.3), which segregates with NS-ARID in three families who come from the same village and probably have shared inheritance. In the Iranian family, the missense mutation c.1000C>T (p.Arg334Cys; RefSeq number NM_016219.3) also segregates with NS-ARID. Both missense mutations are at amino acid residues that are conserved across the animal kingdom, and they either reduce k(cat) by ∼1300-fold or disrupt stable protein expression in mammalian cells. MAN1B1 is one of the few NS-ARID genes with an elevated mutation frequency in patients with NS-ARID from different populations.
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Affiliation(s)
- Muhammad Arshad Rafiq
- Molecular Neuropsychiatry and Development Lab, Neurogenetics Section, Centre for Addiction and Mental Health, Toronto, Ontario, Canada
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47
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Pan S, Wang S, Utama B, Huang L, Blok N, Estes MK, Moremen KW, Sifers RN. Golgi localization of ERManI defines spatial separation of the mammalian glycoprotein quality control system. Mol Biol Cell 2011; 22:2810-22. [PMID: 21697506 PMCID: PMC3154878 DOI: 10.1091/mbc.e11-02-0118] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
The current study provides mechanistic insight into the overlapping dynamics by which glycoprotein folding and quality control use distinct intracellular compartments as part of the proteostasis network in mammalian cells. The Golgi complex has been implicated as a possible component of endoplasmic reticulum (ER) glycoprotein quality control, although the elucidation of its exact role is lacking. ERManI, a putative ER resident mannosidase, plays a rate-limiting role in generating a signal that targets misfolded N-linked glycoproteins for ER-associated degradation (ERAD). Herein we demonstrate that the endogenous human homologue predominantly resides in the Golgi complex, where it is subjected to O-glycosylation. To distinguish the intracellular site where the glycoprotein ERAD signal is generated, a COPI-binding motif was appended to the N terminus of the recombinant protein to facilitate its retrograde translocation back to the ER. Partial redistribution of the modified ERManI was observed along with an accelerated rate at which N-linked glycans of misfolded α1-antitrypsin variant NHK were trimmed. Despite these observations, the rate of NHK degradation was not accelerated, implicating the Golgi complex as the site for glycoprotein ERAD substrate tagging. Taken together, these data provide a potential mechanistic explanation for the spatial separation by which glycoprotein quality control components operate in mammalian cells.
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Affiliation(s)
- Shujuan Pan
- Departments of Pathology & Immunology, Baylor College of Medicine, Houston, TX 77030, USA
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48
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Gregg KJ, Zandberg WF, Hehemann JH, Whitworth GE, Deng L, Vocadlo DJ, Boraston AB. Analysis of a new family of widely distributed metal-independent alpha-mannosidases provides unique insight into the processing of N-linked glycans. J Biol Chem 2011; 286:15586-96. [PMID: 21388958 PMCID: PMC3083162 DOI: 10.1074/jbc.m111.223172] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 02/28/2011] [Indexed: 11/06/2022] Open
Abstract
The modification of N-glycans by α-mannosidases is a process that is relevant to a large number of biologically important processes, including infection by microbial pathogens and colonization by microbial symbionts. At present, the described mannosidases specific for α1,6-mannose linkages are very limited in number. Through structural and functional analysis of two sequence-related enzymes, one from Streptococcus pneumoniae (SpGH125) and one from Clostridium perfringens (CpGH125), a new glycoside hydrolase family, GH125, is identified and characterized. Analysis of SpGH125 and CpGH125 reveal them to have exo-α1,6-mannosidase activity consistent with specificity for N-linked glycans having their α1,3-mannose branches removed. The x-ray crystal structures of SpGH125 and CpGH125 obtained in apo-, inhibitor-bound, and substrate-bound forms provide both mechanistic and molecular insight into how these proteins, which adopt an (α/α)(6)-fold, recognize and hydrolyze the α1,6-mannosidic bond by an inverting, metal-independent catalytic mechanism. A phylogenetic analysis of GH125 proteins reveals this to be a relatively large and widespread family found frequently in bacterial pathogens, bacterial human gut symbionts, and a variety of fungi. Based on these studies we predict this family of enzymes will primarily comprise such exo-α1,6-mannosidases.
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Affiliation(s)
- Katie J. Gregg
- From the Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6 and
| | - Wesley F. Zandberg
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Jan-Hendrik Hehemann
- From the Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6 and
| | - Garrett E. Whitworth
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Lehua Deng
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - David J. Vocadlo
- the Department of Chemistry, Simon Fraser University, Burnaby, British Columbia V5A 1S6, Canada
| | - Alisdair B. Boraston
- From the Department of Biochemistry and Microbiology, University of Victoria, P.O. Box 3055 STN CSC, Victoria, British Columbia V8W 3P6 and
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49
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Stütz AE, Wrodnigg TM. Imino sugars and glycosyl hydrolases: historical context, current aspects, emerging trends. Adv Carbohydr Chem Biochem 2011; 66:187-298. [PMID: 22123190 DOI: 10.1016/b978-0-12-385518-3.00004-3] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Forty years of discoveries and research on imino sugars, which are carbohydrate analogues having a basic nitrogen atom instead of oxygen in the sugar ring and, acting as potent glycosidase inhibitors, have made considerable impact on our contemporary understanding of glycosidases. Imino sugars have helped to elucidate the catalytic machinery of glycosidases and have refined our methods and concepts of utilizing them. A number of new aspects have emerged for employing imino sugars as pharmaceutical compounds, based on their profound effects on metabolic activities in which glycosidases are involved. From the digestion of starch to the fight against viral infections, from research into malignant diseases to potential improvements in hereditary storage disorders, glycosidase action and inhibition are essential issues. This account aims at combining general developments with a focus on some niches where imino sugars have become useful tools for glycochemistry and glycobiology.
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Affiliation(s)
- Arnold E Stütz
- Institut für Organische Chemie, Technische Universität Graz, Austria
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50
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Vuong TV, Wilson DB. Glycoside hydrolases: catalytic base/nucleophile diversity. Biotechnol Bioeng 2010; 107:195-205. [PMID: 20552664 DOI: 10.1002/bit.22838] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Recent studies have shown that a number of glycoside hydrolase families do not follow the classical catalytic mechanisms, as they lack a typical catalytic base/nucleophile. A variety of mechanisms are used to replace this function, including substrate-assisted catalysis, a network of several residues, and the use of non-carboxylate residues or exogenous nucleophiles. Removal of the catalytic base/nucleophile by mutation can have a profound impact on substrate specificity, producing enzymes with completely new functions.
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Affiliation(s)
- Thu V Vuong
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, NY 14850, USA
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