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Kind L, Driver M, Raasakka A, Onck PR, Njølstad PR, Arnesen T, Kursula P. Structural properties of the HNF-1A transactivation domain. Front Mol Biosci 2023; 10:1249939. [PMID: 37908230 PMCID: PMC10613711 DOI: 10.3389/fmolb.2023.1249939] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2023] [Accepted: 09/26/2023] [Indexed: 11/02/2023] Open
Abstract
Hepatocyte nuclear factor 1α (HNF-1A) is a transcription factor with important gene regulatory roles in pancreatic β-cells. HNF1A gene variants are associated with a monogenic form of diabetes (HNF1A-MODY) or an increased risk for type 2 diabetes. While several pancreatic target genes of HNF-1A have been described, a lack of knowledge regarding the structure-function relationships in HNF-1A prohibits a detailed understanding of HNF-1A-mediated gene transcription, which is important for precision medicine and improved patient care. Therefore, we aimed to characterize the understudied transactivation domain (TAD) of HNF-1A in vitro. We present a bioinformatic approach to dissect the TAD sequence, analyzing protein structure, sequence composition, sequence conservation, and the existence of protein interaction motifs. Moreover, we developed the first protocol for the recombinant expression and purification of the HNF-1A TAD. Small-angle X-ray scattering and synchrotron radiation circular dichroism suggested a disordered conformation for the TAD. Furthermore, we present functional data on HNF-1A undergoing liquid-liquid phase separation, which is in line with in silico predictions and may be of biological relevance for gene transcriptional processes in pancreatic β-cells.
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Affiliation(s)
- Laura Kind
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Mark Driver
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Patrick R. Onck
- Zernike Institute for Advanced Materials, University of Groningen, Groningen, Netherlands
| | - Pål Rasmus Njølstad
- Mohn Center for Diabetes Precision Medicine, Department of Clinical Science, University of Bergen, Bergen, Norway
- Section of Endocrinology and Metabolism, Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway
| | - Thomas Arnesen
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Department of Surgery, Haukeland University Hospital, Bergen, Norway
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway
- Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
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2
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El Gizawy HA, El-Haddad AE, Saadeldeen AM, Boshra SA. Tentatively Identified (UPLC/T-TOF-MS/MS) Compounds in the Extract of Saussurea costus Roots Exhibit In Vivo Hepatoprotection via Modulation of HNF-1α, Sirtuin-1, C/ebpα, miRNA-34a and miRNA-223. Molecules 2022; 27:molecules27092802. [PMID: 35566153 PMCID: PMC9104236 DOI: 10.3390/molecules27092802] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 04/25/2022] [Accepted: 04/26/2022] [Indexed: 12/10/2022] Open
Abstract
Saussurea costus is a plant traditionally used for the treatment of several ailments. Our study accomplished the UPLC/T-TOF-MS/MS analysis of a methanol extract of Saussurea costus roots (MESC), in addition to lipoidal matter determination and assessment of its in vivo hepatoprotective activity. In this study, we were able to identify the major metabolites in MESC rather than the previously known isolated compounds, improving our knowledge of its chemical constituents. The flavones apigenin, acacetin, baicalein, luteolin, and diosmetin, and the flavonol aglycones quercetin, kaempferol, isorhamnetin, gossypetin, and myricetin and/or their glycosides and glucuronic derivatives were the major identified compounds. The hepatoprotective activity of MESC was evaluated by measuring catalase activity using UV spectrophotometry, inflammatory cytokines and apoptotic markers using ELISA techniques, and genetic markers using PCR. Paracetamol toxicity caused a significant increase in plasma caspase 2, cytokeratin 18 (CK18), liver tumor necrosis factor-α (TNF-α), interleukin 6 (IL-6), miRNA-34a, and miRNA-223, as well as a significant decrease in liver catalase (CAT) activity and in the levels of liver nuclear factor 1α (HNF-1α), sirtuin-1, and C/ebpα. Oral pretreatment with MESC (200 mg/kg) showed a significant decrease in caspase 2, CK18, TNF-α, IL-6 and a significant increase in liver CAT activity. MESC decreased the levels of liver miRNA-34a and miRNA-223 and induced HNF-1α, sirtuin-1, and C/ebpα gene expression. The histological examination showed a significant normalization in rats pretreated with MESC. Our findings showed that Saussurea costus may exert a potent hepatoprotective activity through the modulation of the expression of cellular cytokines, miRNA-34a, and miRNA-223.
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Affiliation(s)
- Heba A. El Gizawy
- Department of Pharmacognosy, Faculty of Pharmacy, October 6 University (O6U), Giza 12585, Egypt;
| | - Alaadin E. El-Haddad
- Department of Pharmacognosy, Faculty of Pharmacy, October 6 University (O6U), Giza 12585, Egypt;
- Correspondence: or
| | - Amr M. Saadeldeen
- Department of Pharmacognosy, School of Pharmacy, Newgiza University (NGU), Newgiza, km 22 Cairo-Alexandria Desert Road, Giza 12577, Egypt;
| | - Sylvia A. Boshra
- Department of Biochemistry, Faculty of Pharmacy, October 6 University (O6U), Giza 12585, Egypt;
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3
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Kind L, Raasakka A, Molnes J, Aukrust I, Bjørkhaug L, Njølstad PR, Kursula P, Arnesen T. Structural and biophysical characterization of transcription factor HNF-1A as a tool to study MODY3 diabetes variants. J Biol Chem 2022; 298:101803. [PMID: 35257744 PMCID: PMC8988010 DOI: 10.1016/j.jbc.2022.101803] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 02/15/2022] [Accepted: 02/20/2022] [Indexed: 11/05/2022] Open
Abstract
Hepatocyte nuclear factor 1A (HNF-1A) is a transcription factor expressed in several embryonic and adult tissues, modulating the expression of numerous target genes. Pathogenic variants in the HNF1A gene are known to cause maturity-onset diabetes of the young 3 (MODY3 or HNF1A MODY), a disease characterized by dominant inheritance, age of onset before 25 to 35 years of age, and pancreatic β-cell dysfunction. A precise diagnosis can alter management of this disease, as insulin can be exchanged with sulfonylurea tablets and genetic counseling differs from polygenic forms of diabetes. Therefore, more knowledge on the mechanisms of HNF-1A function and the level of pathogenicity of the numerous HNF1A variants is required for precise diagnostics. Here, we structurally and biophysically characterized an HNF-1A protein containing both the DNA-binding domain and the dimerization domain, and determined the folding and DNA-binding capacity of two established MODY3 HNF-1A variant proteins (P112L, R263C) and one variant of unknown significance (N266S). All three variants showed reduced functionality compared to the WT protein. Furthermore, while the R263C and N266S variants displayed reduced binding to an HNF-1A target promoter, we found the P112L variant was unstable in vitro and in cells. Our results support and mechanistically explain disease causality for these investigated variants and present a novel approach for the dissection of structurally unstable and DNA-binding defective variants. This study indicates that structural and biochemical investigation of HNF-1A is a valuable tool in reliable variant classification needed for precision diabetes diagnostics and management.
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Affiliation(s)
- Laura Kind
- Department of Biomedicine, University of Bergen, Bergen, Norway.
| | - Arne Raasakka
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Janne Molnes
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Ingvild Aukrust
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Department of Medical Genetics, Haukeland University Hospital, Bergen, Norway
| | - Lise Bjørkhaug
- Department of Safety, Chemistry, and Biomedical Laboratory Sciences, Western Norway University of Applied Sciences, Bergen, Norway
| | - Pål Rasmus Njølstad
- Center for Diabetes Research, Department of Clinical Science, University of Bergen, Bergen, Norway; Section of Endocrinology and Metabolism, Children and Youth Clinic, Haukeland University Hospital, Bergen, Norway.
| | - Petri Kursula
- Department of Biomedicine, University of Bergen, Bergen, Norway; Faculty of Biochemistry and Molecular Medicine & Biocenter Oulu, University of Oulu, Oulu, Finland
| | - Thomas Arnesen
- Department of Biomedicine, University of Bergen, Bergen, Norway; Department of Biological Sciences, University of Bergen, Bergen, Norway; Department of Surgery, Haukeland University Hospital, Bergen, Norway.
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4
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Muguruza-Montero A, Ramis R, Nuñez E, R Ballesteros O, G Ibarluzea M, Araujo A, M-Alicante S, Urrutia J, Leonardo A, Bergara A, Villarroel A. Do calmodulin binding IQ motifs have built-in capping domains? Protein Sci 2021; 30:2029-2041. [PMID: 34392571 PMCID: PMC8442972 DOI: 10.1002/pro.4170] [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] [Subscribe] [Scholar Register] [Received: 06/21/2021] [Revised: 07/31/2021] [Accepted: 08/04/2021] [Indexed: 01/28/2023]
Abstract
Most calmodulin (CaM) targets are α-helices. It is not clear if CaM induces the adoption of an α-helix configuration to its targets or if those targets are selected as they spontaneously adopt an α-helical conformation. Other than an α-helix propensity, there is a great variety of CaM targets with little more in common. One exception to this rule is the IQ site that can be recognized in a number of targets, such as those ion channels belonging to the KCNQ family. Although there is negligible sequence similarity between the IQ motif and the docking site on SK2 channels, both adopt a similar three-dimensional disposition. The isolated SK2 target presents a pre-folded core region that becomes fully α-helical upon binding to CaM. The existence of this pre-folded state suggests the occurrence of capping within CaM targets. In this review, we examine the capping properties within the residues flanking this core domain, and relate known IQ motifs and capping.
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Affiliation(s)
| | - Rafael Ramis
- Donostia International Physics Center, Donostia, Spain.,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Eider Nuñez
- LaboKCNQ, Barrio Sarriena, Leioa, Spain.,Instituto Biofisika, CSIC-UPV/EHU, Leioa, Spain
| | - Oscar R Ballesteros
- Centro de Física de Materiales CFM, CSIC-UPV/EHU, Donostia, Spain.,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Markel G Ibarluzea
- Donostia International Physics Center, Donostia, Spain.,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Ariane Araujo
- LaboKCNQ, Barrio Sarriena, Leioa, Spain.,Instituto Biofisika, CSIC-UPV/EHU, Leioa, Spain
| | | | - Janire Urrutia
- LaboKCNQ, Barrio Sarriena, Leioa, Spain.,Department of Physiology, Faculty of Medicine and Nursery, UPV/EHU, Leioa, Spain
| | - Aritz Leonardo
- Donostia International Physics Center, Donostia, Spain.,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Aitor Bergara
- Donostia International Physics Center, Donostia, Spain.,Centro de Física de Materiales CFM, CSIC-UPV/EHU, Donostia, Spain.,Departamento de Física, Universidad del País Vasco, UPV/EHU, Leioa, Spain
| | - Alvaro Villarroel
- LaboKCNQ, Barrio Sarriena, Leioa, Spain.,Instituto Biofisika, CSIC-UPV/EHU, Leioa, Spain
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5
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A Review of Functional Characterization of Single Amino Acid Change Mutations in HNF Transcription Factors in MODY Pathogenesis. Protein J 2021; 40:348-360. [PMID: 33950347 DOI: 10.1007/s10930-021-09991-8] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/22/2021] [Indexed: 12/15/2022]
Abstract
Mutations in HNF transcription factor genes cause the most common subtypes of maturity-onset of diabetes of youth (MODY), a monogenic form of diabetes mellitus. Mutations in the HNF1-α, HNF4-α, and HNF1-β genes are primarily considered as the cause of MODY3, MODY1, and MODY5 subtypes, respectively. Although patients with different subtypes display similar symptoms, they may develop distinct diabetes-related complications and require different treatments depending on the type of the mutation. Genetic analysis of MODY patients revealed more than 400 missense/nonsense mutations in HNF1-α, HNF4-α, and HNF1-β genes, however only a small portion of them are functionally characterized. Evaluation of nonsense mutations are more direct as they lead to premature stop codons and mostly in mRNA decay or nonfunctional truncated proteins. However, interpretation of the single amino acid change (missense) mutation is not such definite, as effect of the variant may vary depending on the location and also the substituted amino acid. Mutations with benign effect on the protein function may not be the pathologic variant and further genetic testing may be required. Here, we discuss the functional characterization analysis of single amino acid change mutations identified in HNF1-α, HNF4-α, and HNF1-β genes and evaluate their roles in MODY pathogenesis. This review will contribute to comprehend HNF nuclear family-related molecular mechanisms and to develop more accurate diagnosis and treatment based on correct evaluation of pathologic effects of the variants.
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6
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Wang X, Hassan W, Zhao J, Bakht S, Nie Y, Wang Y, Pang Q, Huang Z. The impact of hepatocyte nuclear factor-1α on liver malignancies and cell stemness with metabolic consequences. Stem Cell Res Ther 2019; 10:315. [PMID: 31685031 PMCID: PMC6829964 DOI: 10.1186/s13287-019-1438-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2019] [Revised: 09/03/2019] [Accepted: 10/01/2019] [Indexed: 01/18/2023] Open
Abstract
Hepatocyte nuclear factor-1 alpha (HNF-1α) is a transcription factor expressed predominantly in the liver among other organs. Structurally, it contains POU-homeodomain that binds to DNA and form proteins that help in maintaining cellular homeostasis, controlling metabolism, and differentiating cell lineages. Scientific research over the period of three decades has reported it as an important player in various liver malignancies such as hepatocellular cancers (HCCs), hepatocellular adenoma (HA), and a more specific HNF-1α-inactivated human hepatocellular adenoma (H-HCAs). Abundant clinical and rodent data have noted the downregulation of HNF-1α in parallel with liver malignancies. It is also interesting to notice that the co-occurrence of mutated HNF-1α expression and hepatic carcinomas transpires typically along with metabolic repercussion. Moreover, scientific data implies that HNF-1α exerts its effects on cell stemness and hence can indirectly impact liver malignancies and metabolic functioning. The effects of HNF-1α on cell stemness present a future opportunity to explore a possible and potential breakthrough. Although the mechanism through which inactivated HNF-1α leads to hepatic malignancies remain largely obscure, several key signal molecules or pathways, including TNF-α, SHP-1, CDH17, SIRT, and MIA-2, have been reported to take part in the regulations of HNF-1α. It can be concluded from the present scientific data that HNF-1α has a great potential to serve as a target for liver malignancies and cell stemness.
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Affiliation(s)
- Xue Wang
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Waseem Hassan
- Department of Pharmacy, COMSATS University Islamabad, Lahore campus, Lahore, Pakistan
| | - Jing Zhao
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Sahar Bakht
- Department of Pharmacy, The Islamia University of Bahawalpur, Bahawalpur, Pakistan
| | - Yunjuan Nie
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi, China
| | - Ying Wang
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi, China.,Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, Wuxi, 214062, Jiangsu, China
| | - Qingfeng Pang
- Department of physiopathology, Wuxi School of Medicine, Jiangnan University, Wuxi, Jiangsu province, China
| | - Zhaohui Huang
- Laboratory of Cancer Epigenetics, Wuxi School of Medicine, Jiangnan University, Wuxi, China. .,Wuxi Cancer Institute, Affiliated Hospital of Jiangnan University, Wuxi, 214062, Jiangsu, China.
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7
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Dietary Metabolites and Chronic Kidney Disease. Nutrients 2017; 9:nu9040358. [PMID: 28375181 PMCID: PMC5409697 DOI: 10.3390/nu9040358] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 03/30/2017] [Accepted: 03/31/2017] [Indexed: 01/04/2023] Open
Abstract
Dietary contents and their metabolites are closely related to chronic kidney disease (CKD) progression. Advanced glycated end products (AGEs) are a type of uremic toxin produced by glycation. AGE accumulation is not only the result of elevated glucose levels or reduced renal clearance capacity, but it also promotes CKD progression. Indoxyl sulfate, another uremic toxin derived from amino acid metabolism, accumulates as CKD progresses and induces tubulointerstitial fibrosis and glomerular sclerosis. Specific types of amino acids (d-serine) or fatty acids (palmitate) are reported to be closely associated with CKD progression. Promising therapeutic targets associated with nutrition include uremic toxin absorbents and inhibitors of AGEs or the receptor for AGEs (RAGE). Probiotics and prebiotics maintain gut flora balance and also prevent CKD progression by enhancing gut barriers and reducing uremic toxin formation. Nrf2 signaling not only ameliorates oxidative stress but also reduces elevated AGE levels. Bardoxolone methyl, an Nrf2 activator and NF-κB suppressor, has been tested as a therapeutic agent, but the phase 3 clinical trial was terminated owing to the high rate of cardiovascular events. However, a phase 2 trial has been initiated in Japan, and the preliminary analysis reveals promising results without an increase in cardiovascular events.
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8
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Takenaka T, Ito T, Miyahara I, Hemmi H, Yoshimura T. A new member of MocR/GabR-type PLP-binding regulator ofd-alanyl-d-alanine ligase inBrevibacillus brevis. FEBS J 2015; 282:4201-17. [DOI: 10.1111/febs.13415] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2015] [Revised: 07/28/2015] [Accepted: 08/12/2015] [Indexed: 11/27/2022]
Affiliation(s)
- Takashi Takenaka
- Department of Applied Molecular Biosciences; Graduate School of Bioagricultural Sciences; Nagoya University; Japan
| | - Tomokazu Ito
- Department of Applied Molecular Biosciences; Graduate School of Bioagricultural Sciences; Nagoya University; Japan
| | - Ikuko Miyahara
- Department of Chemistry; Graduate School of Science; Osaka City University; Japan
| | - Hisashi Hemmi
- Department of Applied Molecular Biosciences; Graduate School of Bioagricultural Sciences; Nagoya University; Japan
| | - Tohru Yoshimura
- Department of Applied Molecular Biosciences; Graduate School of Bioagricultural Sciences; Nagoya University; Japan
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9
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Abstract
Background Interactions that involve one or more amino acid side chains near the ends of protein helices stabilize helix termini and shape the geometry of the adjacent loops, making a substantial contribution to overall protein structure. Previous work has identified key helix-terminal motifs, such as Asx/ST N-caps, the capping box, and hydrophobic and electrostatic interactions, but important questions remain, including: 1) What loop backbone geometries are favoured by each motif? 2) To what extent are multi-amino acid motifs likely to represent genuine cooperative interactions? 3) Can new motifs be identified in a large, recent dataset using the latest bioinformatics tools? Results Three analytical tools are applied here to answer these questions. First, helix-terminal structures are partitioned by loop backbone geometry using a new 3D clustering algorithm. Next, Cascade Detection, a motif detection algorithm recently published by the author, is applied to each cluster to determine which sequence motifs are overrepresented in each geometry. Finally, the results for each motif are presented in a CapMap, a 3D conformational heatmap that displays the distribution of the motif’s overrepresentation across loop geometries, enabling the rapid isolation and characterization of the associated side chain interaction. This work identifies a library of geometry-specific side chain interactions that provides a new, detailed picture of loop structure near the helix terminus. Highlights include determinations of the favoured loop geometries for the Asx/ST N-cap motifs, capping boxes, “big” boxes, and other hydrophobic, electrostatic, H-bond, and pi stacking interactions, many of which have not been described before. Conclusions This work demonstrates that the combination of structural clustering and motif detection in the sequence space can efficiently identify side chain motifs and map them to the loop geometries which they support. Protein designers should find this study useful, because it identifies side chain interactions which are good candidates for inclusion in synthetic helix-terminal loops with specific desired geometries, since they are used in nature to support these geometries. The techniques described here can also be applied to map side chain interactions associated with other structural components of proteins such as beta and gamma turns. Electronic supplementary material The online version of this article (doi:10.1186/s12859-015-0671-4) contains supplementary material, which is available to authorized users.
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10
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Ali H, Urolagin S, Gurarslan Ö, Vihinen M. Performance of Protein Disorder Prediction Programs on Amino Acid Substitutions. Hum Mutat 2014; 35:794-804. [DOI: 10.1002/humu.22564] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Accepted: 04/04/2014] [Indexed: 01/04/2023]
Affiliation(s)
- Heidi Ali
- Institute of Biomedical Technology; FI-33014 University of Tampere; Tampere Finland
- BioMediTech; Tampere Finland
| | - Siddhaling Urolagin
- Department of Experimental Medical Science; Lund University; SE-22184 Lund Sweden
| | - Ömer Gurarslan
- Institute of Biomedical Technology; FI-33014 University of Tampere; Tampere Finland
- BioMediTech; Tampere Finland
| | - Mauno Vihinen
- Institute of Biomedical Technology; FI-33014 University of Tampere; Tampere Finland
- BioMediTech; Tampere Finland
- Department of Experimental Medical Science; Lund University; SE-22184 Lund Sweden
- Tampere University Hospital; Tampere Finland
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11
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Li W, Nicola JP, Amzel LM, Carrasco N. Asn441 plays a key role in folding and function of the Na+/I- symporter (NIS). FASEB J 2013; 27:3229-38. [PMID: 23650190 DOI: 10.1096/fj.13-229138] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
The Na(+)/I(-) symporter (NIS) is a plasma membrane glycoprotein that mediates active I(-) transport in the thyroid, the first step in the biosynthesis of the iodine-containing thyroid hormones T3 and T4. Several NIS mutants have been identified as a cause of congenital I(-) transport defect (ITD), and their investigation has yielded valuable mechanistic information on NIS. Here we report a thorough characterization of the ITD-causing NIS mutation in which the sixth intracellular loop residues 439-443 are missing. This mutant protein was intracellularly retained, incompletely glycosylated, and intrinsically inactive. Engineering 5 Ala at positions 439-443 partially recovered cell surface targeting and activity (∼15%). Strikingly, NIS with the sequence 439-AANAA-443, in which Asn was restored at position 441, was targeted to the plasma membrane and exhibited ∼95% the transport activity of WT NIS. Based on our NIS homology model, we propose that the side chain of N441, a residue conserved throughout most of the SLC5 family, interacts with the main chain amino group of G444, capping the α-helix of transmembrane segment XII and thus stabilizing the structure of the molecule. Our data provide insight into a critical interhelical interaction required for NIS folding and activity.
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Affiliation(s)
- Wenjing Li
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, New York, USA
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12
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Luo Y, Lin L, Bolund L, Jensen TG, Sørensen CB. Genetically modified pigs for biomedical research. J Inherit Metab Dis 2012; 35:695-713. [PMID: 22453682 DOI: 10.1007/s10545-012-9475-0] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/16/2011] [Revised: 02/09/2012] [Accepted: 03/02/2012] [Indexed: 01/17/2023]
Abstract
During the last two decades, pigs have been used to develop some of the most important large animal models for biomedical research. Advances in pig genome research, genetic modification (GM) of primary pig cells and pig cloning by nuclear transfer, have facilitated the generation of GM pigs for xenotransplantation and various human diseases. This review summarizes the key technologies used for generating GM pigs, including pronuclear microinjection, sperm-mediated gene transfer, somatic cell nuclear transfer by traditional cloning, and somatic cell nuclear transfer by handmade cloning. Broadly used genetic engineering tools for porcine cells are also discussed. We also summarize the GM pig models that have been generated for xenotransplantation and human disease processes, including neurodegenerative diseases, cardiovascular diseases, eye diseases, bone diseases, cancers and epidermal skin diseases, diabetes mellitus, cystic fibrosis, and inherited metabolic diseases. Thus, this review provides an overview of the progress in GM pig research over the last two decades and perspectives for future development.
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Affiliation(s)
- Yonglun Luo
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark.
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13
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Rodriguez-Granillo A, Annavarapu S, Zhang L, Koder RL, Nanda V. Computational design of thermostabilizing D-amino acid substitutions. J Am Chem Soc 2011; 133:18750-9. [PMID: 21978298 PMCID: PMC3443866 DOI: 10.1021/ja205609c] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Judicious incorporation of D-amino acids in engineered proteins confers many advantages such as preventing degradation by endogenous proteases and promoting novel structures and functions not accessible to homochiral polypeptides. Glycine to D-alanine substitutions at the carboxy termini can stabilize α-helices by reducing conformational entropy. Beyond alanine, we propose additional side chain effects on the degree of stabilization conferred by D-amino acid substitutions. A detailed, molecular understanding of backbone and side chain interactions is important for developing rational, broadly applicable strategies in using D-amino acids to increase protein thermostability. Insight from structural bioinformatics combined with computational protein design can successfully guide the selection of stabilizing D-amino acid mutations. Substituting a key glycine in the Trp-cage miniprotein with D-Gln dramatically stabilizes the fold without altering the protein backbone. Stabilities of individual substitutions can be understood in terms of the balance of intramolecular forces both at the α-helix C-terminus and throughout the protein.
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Affiliation(s)
- Agustina Rodriguez-Granillo
- Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ and the Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey 08854
| | - Srinivas Annavarapu
- Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ and the Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey 08854
| | - Lei Zhang
- Department of Physics, The City College of New York, New York, New York 10031
| | - Ronald L. Koder
- Department of Physics, The City College of New York, New York, New York 10031
| | - Vikas Nanda
- Department of Biochemistry, Robert Wood Johnson Medical School, UMDNJ and the Center for Advanced Biotechnology and Medicine, Piscataway, New Jersey 08854
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Segura J, Oliva B, Fernandez-Fuentes N. CAPS-DB: a structural classification of helix-capping motifs. Nucleic Acids Res 2011; 40:D479-85. [PMID: 22021380 PMCID: PMC3245141 DOI: 10.1093/nar/gkr879] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
The regions of the polypeptide chain immediately preceding or following an α-helix are known as Nt- and Ct cappings, respectively. Cappings play a central role stabilizing α-helices due to lack of intrahelical hydrogen bonds in the first and last turn. Sequence patterns of amino acid type preferences have been derived for cappings but the structural motifs associated to them are still unclassified. CAPS-DB is a database of clusters of structural patterns of different capping types. The clustering algorithm is based in the geometry and the (ϕ–ψ)-space conformation of these regions. CAPS-DB is a relational database that allows the user to search, browse, inspect and retrieve structural data associated to cappings. The contents of CAPS-DB might be of interest to a wide range of scientist covering different areas such as protein design and engineering, structural biology and bioinformatics. The database is accessible at: http://www.bioinsilico.org/CAPSDB.
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Affiliation(s)
- Joan Segura
- Leeds Institute of Molecular Medicine, Section of Experimental Therapeutics, University of Leeds, St James's University Hospital, Leeds LS9 7TF, UK
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Annavarapu S, Nanda V. Mirrors in the PDB: left-handed alpha-turns guide design with D-amino acids. BMC STRUCTURAL BIOLOGY 2009; 9:61. [PMID: 19772623 PMCID: PMC2759939 DOI: 10.1186/1472-6807-9-61] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/24/2009] [Accepted: 09/22/2009] [Indexed: 11/28/2022]
Abstract
Background Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Results Propensities for amino acids to occur in contiguous αL helices correlate with published thermodynamic scales for incorporation of D-amino acids into αR helices. Two backbone rules for terminating a left-handed helix are found: an αR conformation is disfavored at the amino terminus, and a βR conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to αL helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. Conclusion By examining left-handed α-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed α-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds.
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Affiliation(s)
- Srinivas Annavarapu
- Department of Biochemistry, Robert Wood Johnson Medical School, University of Medicine and Dentistry of New Jersey, Piscataway, NJ 08854, USA.
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