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Vuksanovic N, Melkonian TR, Serrano DA, Schwabacher AW, Silvaggi NR. Structural and Biochemical Characterization of MppQ, an L-Enduracididine Biosynthetic Enzyme from Streptomyces hygroscopicus. Biochemistry 2023; 62:3105-3115. [PMID: 37890134 DOI: 10.1021/acs.biochem.3c00428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/29/2023]
Abstract
MppQ is an enzyme of unknown function from Streptomyces hygroscopicus (ShMppQ) that operates in the biosynthesis of the nonproteinogenic amino acid L-enduracididine (L-End). Since L-End is a component of several peptides showing activity against antibiotic-resistant pathogens, understanding its biosynthetic pathway could facilitate the development of chemoenzymatic routes to novel antibiotics. Herein, we report on the crystal structures of ShMppQ complexed with pyridoxal-5'-phosphate (PLP) and pyridoxamine-5'-phosphate (PMP). ShMppQ is similar to fold-type I PLP-dependent aminotransferases like aspartate aminotransferase. The tertiary structure of ShMppQ is composed of an N-terminal extension, a large domain, and a small domain. The active site is placed at the junction of the large and small domains and includes residues from both protomers of the homodimer. We also report the first functional characterization of MppQ, which we incubated with the enzymatically produced 2-ketoenduracidine and observed the conversion to L-End, establishing ShMppQ as the final enzyme in L-End biosynthesis. Additionally, we have observed that MppQ has a relatively high affinity for 2-keto-5-guanidinovaleric acid (i.e., 2-ketoarginine), a shunt product of MppP, indicating the potential role of MppQ in increasing the efficiency of L-End biosynthesis by converting 2-ketoarginine back to the starting material, l-arginine. A panel of potential amino-donor substrates was tested for the transamination activity against a saturating concentration of 2-ketoarginine in end-point assays. Most l-Arg was produced with l-ornithine as the donor substrate. Steady-state kinetic analysis of the transamination reaction with l-Orn and 2-ketoarginine shows that the kinetic constants are in line with those for the amino donor substrate of other fold-type I aminotransferases.
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Affiliation(s)
- Nemanja Vuksanovic
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
- Department of Chemistry, Boston University, 590 Commonwealth Avenue, Boston, Massachusetts 02215, United States
| | - Trevor R Melkonian
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
- Division of Chemical Biology and Medicinal Chemistry, The University of Texas at Austin, Austin, Texas 78712, United States
| | - Dante A Serrano
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
- Department of Chemistry, Pennsylvania State University, 302 Chemistry Building, University Park, Pennsylvania 16802, United States
| | - Alan W Schwabacher
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
| | - Nicholas R Silvaggi
- Department of Chemistry and Biochemistry, University of Wisconsin-Milwaukee, 3210 North Cramer Street, Milwaukee, Wisconsin 53211, United States
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Kudo F, Kitayama Y, Miyanaga A, Numakura M, Eguchi T. Stepwise Post-glycosylation Modification of Sugar Moieties in Kanamycin Biosynthesis. Chembiochem 2021; 22:1668-1675. [PMID: 33403742 DOI: 10.1002/cbic.202000839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2020] [Revised: 01/05/2021] [Indexed: 11/07/2022]
Abstract
Kanamycin A is the major 2-deoxystreptamine (2DOS)-containing aminoglycoside antibiotic produced by Streptomyces kanamyceticus. The 2DOS moiety is linked with 6-amino-6-deoxy-d-glucose (6ADG) at O-4 and 3-amino-3-deoxy-d-glucose at O-6. Because the 6ADG moiety is derived from d-glucosamine (GlcN), deamination at C-2 and introduction of C-6-NH2 are required in the biosynthesis. A dehydrogenase, KanQ, and an aminotransferase, KanB, are presumed to be responsible for the introduction of C-6-NH2 , although the substrates have not been identified. Here, we examined the substrate specificity of KanQ to better understand the biosynthetic pathway. It was found that KanQ oxidized kanamycin C more efficiently than the 3''-deamino derivative. Furthermore, the substrate specificity of an oxygenase, KanJ, that is responsible for deamination at C-2 of the GlcN moiety was examined, and the crystal structure of KanJ was determined. It was found that C-6-NH2 is important for substrate recognition by KanJ. Thus, the modification of the GlcN moiety occurs after pseudo-trisaccharide formation, followed by the introduction of C-6-NH2 by KanQ/KanB and deamination at C-2 by KanJ.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Yukinobu Kitayama
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Mario Numakura
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 O-okayama, Meguro-ku, Tokyo, 152-8551, Japan
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Kudo F, Mori A, Koide M, Yajima R, Takeishi R, Miyanaga A, Eguchi T. One-pot enzymatic synthesis of 2-deoxy-scyllo-inosose from d-glucose and polyphosphate. Biosci Biotechnol Biochem 2021; 85:108-114. [PMID: 33577648 DOI: 10.1093/bbb/zbaa025] [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: 08/05/2020] [Accepted: 08/27/2020] [Indexed: 11/14/2022]
Abstract
2-Deoxy-scyllo-inosose (2DOI, [2S,3R,4S,5R]-2,3,4,5-tetrahydroxycyclohexan-1-one) is a biosynthetic intermediate of 2-deoxystreptamine-containing aminoglycoside antibiotics, including butirosin, kanamycin, and neomycin. In producer microorganisms, 2DOI is constructed from d-glucose 6-phosphate (G6P) by 2-deoxy-scyllo-inosose synthase (DOIS) with the oxidized form of nicotinamide adenine dinucleotide (NAD+). 2DOI is also known as a sustainable biomaterial for production of aromatic compounds and a chiral cyclohexane synthon. In this study, a one-pot enzymatic synthesis of 2DOI from d-glucose and polyphosphate was investigated. First, 3 polyphosphate glucokinases (PPGKs) were examined to produce G6P from d-glucose and polyphosphate. A PPGK derived from Corynebacterium glutamicum (cgPPGK) was found to be suitable for G6P production under ordinary enzymatic conditions. Next, 7 DOISs were examined for the one-pot enzymatic reaction. As a result, cgPPGK and BtrC, the latter of which is a DOIS derived from the butirosin producer Bacillus circulans, achieved nearly full conversion of d-glucose to 2DOI in the presence of polyphosphate.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Ayaka Mori
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Mai Koide
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Ryo Yajima
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Ryohei Takeishi
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Akimasa Miyanaga
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
| | - Tadashi Eguchi
- Department of Chemistry, Tokyo Institute of Technology, O-okayama, Meguro-ku, Tokyo, Japan
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4
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Complete reconstitution of the diverse pathways of gentamicin B biosynthesis. Nat Chem Biol 2019; 15:295-303. [PMID: 30643280 PMCID: PMC6488028 DOI: 10.1038/s41589-018-0203-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2018] [Accepted: 11/13/2018] [Indexed: 11/13/2022]
Abstract
Gentamicin B (GB), a valuable starting material for the preparation of the semisynthetic aminoglycoside antibiotic isepamicin, is produced in trace amounts by the wild-type Micromonospora echinospora. While the biosynthetic pathway to GB has remained obscure for decades, we have now identified three hidden pathways to GB production via seven hitherto unknown intermediates in M. echinospora. The narrow substrate specificity of a key glycosyltransferase and the C6′-amination enzymes, in combination with the weak and unsynchronized gene expression of the 2′-deamination enzymes, limit GB production in M. echinospora. The crystal structure of the aminotransferase involved in C6′-amination explains its substrate specificity. Some of the new intermediates displayed similar premature termination codon readthrough activity but with reduced toxicity compared to the natural aminoglycoside G418. This work not only led to the discovery of unknown biosynthetic routes to GB, but also demonstrated the potential to mine new aminoglycosides from nature for drug discovery.
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Zachman-Brockmeyer TR, Thoden JB, Holden HM. The structure of RbmB from Streptomyces ribosidificus, an aminotransferase involved in the biosynthesis of ribostamycin. Protein Sci 2017; 26:1886-1892. [PMID: 28685903 DOI: 10.1002/pro.3221] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2017] [Revised: 06/23/2017] [Accepted: 06/29/2017] [Indexed: 11/11/2022]
Abstract
Aminoglycoside antibiotics represent a classical group of antimicrobials first discovered in the 1940s. Due to their ototoxic and nephrotoxic side effects, they are typically only used against Gram negative bacteria which have become resistant to other therapeutics. One family of aminoglycosides includes such compounds as butirosin, ribostamycin, neomycin, and kanamycin, amongst others. The common theme in these antibiotics is that they are constructed around a chemically stable aminocyclitol unit referred to as 2-deoxystreptamine (2-DOS). Four enzymes are required for the in vivo production of 2-DOS. Here, we report the structure of RbmB from Streptomyces ribosidificus, which is a pyridoxal 5'-phosphate dependent enzyme that catalyzes two of the required steps in 2-DOS formation by functioning on distinct substrates. For this analysis, the structure of the external aldimine form of RbmB with 2-DOS was determined to 2.1 Å resolution. In addition, the structure of a similar enzyme, BtrR from Bacillus circulans, was also determined to 2.1 Å resolution in the same external aldimine form. These two structures represent the first detailed molecular descriptions of the active sites for those aminotransferases involved in 2-DOS production. Given the fact that the 2-DOS unit is widespread amongst aminoglycoside antibiotics, the data presented herein provide new molecular insight into the biosynthesis of these sugar-based drugs.
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Affiliation(s)
| | - James B Thoden
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin
| | - Hazel M Holden
- Department of Biochemistry, University of Wisconsin, Madison, Wisconsin
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6
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Uddin R, Rafi S. Structural and functional characterization of a unique hypothetical protein (WP_003901628.1) of Mycobacterium tuberculosis: a computational approach. Med Chem Res 2017. [DOI: 10.1007/s00044-017-1822-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
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Zhu Y, Xu J, Mei X, Feng Z, Zhang L, Zhang Q, Zhang G, Zhu W, Liu J, Zhang C. Biochemical and Structural Insights into the Aminotransferase CrmG in Caerulomycin Biosynthesis. ACS Chem Biol 2016; 11:943-52. [PMID: 26714051 DOI: 10.1021/acschembio.5b00984] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Caerulomycin A (CRM A 1) belongs to a family of natural products containing a 2,2'-bipyridyl ring core structure and is currently under development as a potent novel immunosuppressive agent. Herein, we report the functional characterization, kinetic analysis, substrate specificity, and structure insights of an aminotransferase CrmG in 1 biosynthesis. The aminotransferase CrmG was confirmed to catalyze a key transamination reaction to convert an aldehyde group to an amino group in the 1 biosynthetic pathway, preferring l-glutamate and l-glutamine as the amino donor substrates. The crystal structures of CrmG in complex with the cofactor 5'-pyridoxal phosphate (PLP) or 5'-pyridoxamine phosphate (PMP) or the acceptor substrate were determined to adopt a canonical fold-type I of PLP-dependent enzymes with a unique small additional domain. The structure guided site-directed mutagenesis identified key amino acid residues for substrate binding and catalytic activities, thus providing insights into the transamination mechanism of CrmG.
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Affiliation(s)
- Yiguang Zhu
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology,
South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Jinxin Xu
- Key
Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Xiangui Mei
- Key
Laboratory of Marine Drugs, Ministry of Education of China, School
of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Zhan Feng
- Key
Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Liping Zhang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology,
South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Qingbo Zhang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology,
South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Guangtao Zhang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology,
South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
| | - Weiming Zhu
- Key
Laboratory of Marine Drugs, Ministry of Education of China, School
of Medicine and Pharmacy, Ocean University of China, Qingdao 266003, China
| | - Jinsong Liu
- Key
Laboratory of Respiratory Disease, Guangzhou Institutes of Biomedicine
and Health, Chinese Academy of Sciences, Guangzhou 510530, China
| | - Changsheng Zhang
- CAS
Key Laboratory of Tropical Marine Bio-resources and Ecology, Guangdong
Key Laboratory of Marine Materia Medica, RNAM Center for Marine Microbiology,
South China Sea Institute of Oceanology, Chinese Academy of Sciences, 164 West Xingang Road, Guangzhou 510301, China
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8
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Kudo F, Eguchi T. Aminoglycoside Antibiotics: New Insights into the Biosynthetic Machinery of Old Drugs. CHEM REC 2015; 16:4-18. [PMID: 26455715 DOI: 10.1002/tcr.201500210] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Indexed: 11/07/2022]
Abstract
2-Deoxystreptamine (2DOS) is the unique chemically stable aminocyclitol scaffold of clinically important aminoglycoside antibiotics such as neomycin, kanamycin, and gentamicin, which are produced by Actinomycetes. The 2DOS core can be decorated with various deoxyaminosugars to make structurally diverse pseudo-oligosaccharides. After the discovery of biosynthetic gene clusters for 2DOS-containing aminoglycoside antibiotics, the function of each biosynthetic enzyme has been extensively elucidated. The common biosynthetic intermediates 2DOS, paromamine and ribostamycin are constructed by conserved enzymes encoded in the gene clusters. The biosynthetic intermediates are then converted to characteristic architectures by unique enzymes encoded in each biosynthetic gene cluster. In this Personal Account, we summarize both common biosynthetic pathways and the pathways used for structural diversification.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
| | - Tadashi Eguchi
- Department of Chemistry and Materials Science, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, 152-8551, Japan
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9
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Romo AJ, Liu HW. Mechanisms and structures of vitamin B(6)-dependent enzymes involved in deoxy sugar biosynthesis. BIOCHIMICA ET BIOPHYSICA ACTA 2011; 1814:1534-47. [PMID: 21315852 PMCID: PMC3115481 DOI: 10.1016/j.bbapap.2011.02.003] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/15/2010] [Revised: 01/08/2011] [Accepted: 02/01/2011] [Indexed: 10/18/2022]
Abstract
PLP is well-regarded for its role as a coenzyme in a number of diverse enzymatic reactions. Transamination, deoxygenation, and aldol reactions mediated by PLP-dependent enzymes enliven and enrich deoxy sugar biosynthesis, endowing these compounds with unique structures and contributing to their roles as determinants of biological activity in many natural products. The importance of deoxy aminosugars in natural product biosynthesis has spurred several recent structural investigations of sugar aminotransferases. The structure of a PMP-dependent enzyme catalyzing the C-3 deoxygenation reaction in the biosynthesis of ascarylose was also determined. These studies, and the crystal structures they have provided, offer a wealth of new insights regarding the enzymology of PLP/PMP-dependent enzymes in deoxy sugar biosynthesis. In this review, we consider these recent achievements in the structural biology of deoxy sugar biosynthetic enzymes and the important implications they hold for understanding enzyme catalysis and natural product biosynthesis in general. This article is part of a Special Issue entitled: Pyridoxal Phosphate Enzymology.
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Affiliation(s)
- Anthony J. Romo
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712
| | - Hung-wen Liu
- Division of Medicinal Chemistry, College of Pharmacy, and Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, Texas 78712
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10
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Nepal KK, Oh TJ, Sohng JK. Heterologous production of paromamine in Streptomyces lividans TK24 using kanamycin biosynthetic genes from Streptomyces kanamyceticus ATCC12853. Mol Cells 2009; 27:601-8. [PMID: 19466609 DOI: 10.1007/s10059-009-0080-5] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 03/26/2009] [Accepted: 03/30/2009] [Indexed: 10/20/2022] Open
Abstract
The 2-deoxystreptamine and paromamine are two key intermediates in kanamycin biosynthesis. In the present study, pSK-2 and pSK-7 recombinant plasmids were constructed with two combinations of genes: kanABK and kanABKF and kacA respectively from kanamycin producer Streptomyces kanamyceticus ATCC12853. These plasmids were heterologously expressed into Streptomyces lividans TK24 independently and generated two recombinant strains named S. lividans Sk-2/SL and S. lividans SK-7/SL, respectively. ESI/ MS and ESI-LC/MS analysis of the metabolite from S. lividans SK-2/SL showed that the compound had a molecular mass of 163 [M + H]+, which corresponds to that of 2-deoxystreptamine. ESI/MS and MS/MS analysis of metabolites from S. lividans SK-7/SL demonstrated the production of paromamine with a molecular mass of 324 [M + H]+. In this study, we report the production of paromamine in a heterologous host for the first time. This study will evoke to explore complete biosynthetic pathways of kanamycin and related aminoglycoside antibiotics.
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11
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Mahmud T. Progress in aminocyclitol biosynthesis. Curr Opin Chem Biol 2009; 13:161-70. [PMID: 19321377 DOI: 10.1016/j.cbpa.2009.02.030] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 02/16/2009] [Accepted: 02/20/2009] [Indexed: 10/21/2022]
Abstract
A stream of genetic and biochemical information available for the biosynthesis of aminocyclitols over the past few years has provided the foundation to study the modes of formation of this clinically important class of natural products. In addition to work on the identification and functional analysis of aminocyclitol biosynthetic gene clusters, a contingent of recent studies has focused on the detailed analysis of unique enzymatic and catalytic mechanisms inherent to these pathways. The results provide invaluable insights into the biochemical and molecular aspects of aminocyclitol biosynthesis and have revealed diverse and unique features of the pathways.
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Affiliation(s)
- Taifo Mahmud
- Department of Pharmaceutical Sciences, Oregon State University, Corvallis, OR 97331-3507, USA.
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12
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Abstract
Butirosin and neomycin belong to a family of clinically valuable 2-deoxystreptamine (2DOS)-containing aminoglycoside antibiotics. The biosynthetic gene clusters for butirosin and neomycin were identified in 2000 and in 2005, respectively. In recent years, most of the enzymes encoded in the gene clusters have been characterized, and thus almost all the biosynthetic steps leading to the final antibiotics have been understood. This knowledge could shed light on the complex biosynthetic pathways for other related structurally diverse aminoglycoside antibiotics. In this chapter, the enzymatic reactions in the biosynthesis of butirosin and neomycin are reviewed step by step.
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Affiliation(s)
- Fumitaka Kudo
- Department of Chemistry, Tokyo Institute of Technology, Tokyo, Japan
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13
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Smith P, Szu PH, Bui C, Liu HW, Tsai SC. Structure and mutagenic conversion of E1 dehydrase: at the crossroads of dehydration, amino transfer, and epimerization. Biochemistry 2008; 47:6329-41. [PMID: 18491919 DOI: 10.1021/bi702449p] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Pyridoxal 5'-phosphate (PLP) and pyridoxamine 5'-phosphate (PMP) are highly versatile coenzymes whose importance is well recognized. The capability of PLP/PMP-dependent enzymes to catalyze a diverse array of chemical reactions is attributed to fine-tuning of the cofactor-substrate interactions in the active site. CDP-6-deoxy-L-threo-D-glycero-4-hexulose 3-dehydrase (E1), along with its reductase (E3), catalyzes the C-3 deoxygenation of CDP-4-keto-6-deoxy-D-glucose to form the dehydrated product, CDP-4-keto-3,6-dideoxy- d-glucose, in the ascarylose biosynthetic pathway. This product is the progenitor to most 3,6-dideoxyhexoses, which are the major antigenic determinants of many Gram-negative pathogens. The dimeric [2Fe-2S] protein, E 1, cloned from Yersinia pseudotuberculosis, is the only known enzyme whose catalysis involves the direct participation of PMP in one-electron redox chemistry. E1 also contains an unusual [2Fe-2S] cluster with a previously unknown binding motif (C-X 57-C-X 1-C-X 7-C). Herein we report the first X-ray crystal structure of E1, which exhibits an aspartate aminotransferase (AAT) fold. A comparison of the E1 active site architecture with homologous structures uncovers residues critical for the dehydration versus transamination activity. Site-directed mutagenesis of four E1 residues, D194H, Y217H, H220K, and F345H, converted E 1 from a PMP-dependent dehydrase to a PLP/glutamate-dependent aminotransferase. The E1 quadruple mutant, having been conferred this altered enzyme activity, can transaminate the natural substrate to CDP-4,6-dideoxy-4-amino-D-galactose without E3. Taken together, these results provide the molecular basis of the functional switch of E1 toward dehydration, epimerization, and transamination. The insights gained from these studies can be used for the development of inhibitors of disease-relevant PLP/PMP-dependent enzymes.
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Affiliation(s)
- Peter Smith
- Department of Molecular Biology and Biochemistry, University of California, Irvine, Irvine, California 92697, USA
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Identification and diversity of putative aminoglycoside-biosynthetic aminotransferase genes from deep-sea environmental DNA. Biosci Biotechnol Biochem 2008; 72:1388-93. [PMID: 18460796 DOI: 10.1271/bbb.80033] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
We obtained DNA fragments encoding putative aminotransferases possibly involved in the biosynthesis of aminoglycoside antibiotics from deep-sea sediments of the northwest Pacific Ocean by nested PCR, and 34 individual genes (total 89 clones) were identified. About half of the deep-sea sequences showed similarity with genes of known aminoglycoside-producers, but others were deep-sea specific genes. Furthermore, we found that temperature-gradient gel electrophoresis (TGGE) can be an effective tool in the analysis of these DNA fragments.
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15
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Leadlay P. Obituary: Jonathan B. Spencer (1960-2008). CHEMISTRY & BIOLOGY 2008; 15:424-426. [PMID: 18551814 DOI: 10.1016/j.chembiol.2008.05.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Affiliation(s)
- Peter Leadlay
- Department of Biochemistry, University of Cambridge, Cambridge, UK.
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16
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Cellini B, Bertoldi M, Montioli R, Paiardini A, Borri Voltattorni C. Human wild-type alanine:glyoxylate aminotransferase and its naturally occurring G82E variant: functional properties and physiological implications. Biochem J 2007; 408:39-50. [PMID: 17696873 PMCID: PMC2049084 DOI: 10.1042/bj20070637] [Citation(s) in RCA: 77] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Human hepatic peroxisomal AGT (alanine:glyoxylate aminotransferase) is a PLP (pyridoxal 5'-phosphate)-dependent enzyme whose deficiency causes primary hyperoxaluria Type I, a rare autosomal recessive disorder. To acquire experimental evidence for the physiological function of AGT, the K(eq),(overall) of the reaction, the steady-state kinetic parameters of the forward and reverse reactions, and the pre-steady-state kinetics of the half-reactions of the PLP form of AGT with L-alanine or glycine and the PMP (pyridoxamine 5'-phosphate) form with pyruvate or glyoxylate have been measured. The results indicate that the enzyme is highly specific for catalysing glyoxylate to glycine processing, thereby playing a key role in glyoxylate detoxification. Analysis of the reaction course also reveals that PMP remains bound to the enzyme during the catalytic cycle and that the AGT-PMP complex displays a reactivity towards oxo acids higher than that of apoAGT in the presence of PMP. These findings are tentatively related to possible subtle rearrangements at the active site also indicated by the putative binding mode of catalytic intermediates. Additionally, the catalytic and spectroscopic features of the naturally occurring G82E variant have been analysed. Although, like the wild-type, the G82E variant is able to bind 2 mol PLP/dimer, it exhibits a significant reduced affinity for PLP and even more for PMP compared with wild-type, and an altered conformational state of the bound PLP. The striking molecular defect of the mutant, consisting in the dramatic decrease of the overall catalytic activity (approximately 0.1% of that of normal AGT), appears to be related to the inability to undergo an efficient transaldimination of the PLP form of the enzyme with amino acids as well as an efficient conversion of AGT-PMP into AGT-PLP. Overall, careful biochemical analyses have allowed elucidation of the mechanism of action of AGT and the way in which the disease causing G82E mutation affects it.
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Affiliation(s)
- Barbara Cellini
- *Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
| | - Mariarita Bertoldi
- *Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
| | - Riccardo Montioli
- *Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
| | - Alessandro Paiardini
- †Dipartimento di Scienze Biochimiche ‘A. Rossi Fanelli’ and Centro di Biologia Molecolare del Consiglio Nazionale delle Ricerche, Università ‘La Sapienza’, 00185 Roma, Italy
| | - Carla Borri Voltattorni
- *Dipartimento di Scienze Morfologico-Biomediche, Sezione di Chimica Biologica, Facoltà di Medicina e Chirurgia, Università degli Studi di Verona, Strada Le Grazie, 8, 37134 Verona, Italy
- To whom correspondence should be addressed (email )
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Llewellyn NM, Spencer JB. Biosynthesis of 2-deoxystreptamine-containing aminoglycoside antibiotics. Nat Prod Rep 2006; 23:864-74. [PMID: 17119636 DOI: 10.1039/b604709m] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
The 2-deoxystreptamine-containing aminoglycosides are an important class of clinically valuable antibiotics. A deep understanding of the biosynthesis of these natural products is required to enable efforts to rationally manipulate and engineer the biological production of novel aminoglycosides. This review discusses the development of our biosynthetic knowledge over the past half-century, with emphasis on the relatively recent contributions of molecular biology to the elucidation of these biosynthetic pathways.
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Affiliation(s)
- Nicholas M Llewellyn
- Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UKCB2 1EW.
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