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Titolo:
Two sequence elements of glycosyltransferases involved in urdamycin biosynthesis are responsible for substrate specificity and enzymatic activity
Autore:
Hoffmeister, D; Ichinose, K; Bechthold, A;
Indirizzi:
Univ Freiburg, D-79104 Freiburg, Germany Univ Freiburg Freiburg Germany D-79104 eiburg, D-79104 Freiburg, Germany Univ Tokyo, Grad Sch Pharmaceut Sci, Bunkyo Ku, Tokyo 1130033, Japan Univ Tokyo Tokyo Japan 1130033 ceut Sci, Bunkyo Ku, Tokyo 1130033, Japan
Titolo Testata:
CHEMISTRY & BIOLOGY
fascicolo: 6, volume: 8, anno: 2001,
pagine: 557 - 567
SICI:
1074-5521(200106)8:6<557:TSEOGI>2.0.ZU;2-O
Fonte:
ISI
Lingua:
ENG
Soggetto:
STREPTOMYCES-FRADIAE TU2717; CRYSTAL-STRUCTURE; ESCHERICHIA-COLI; GENE-CLUSTER; SACCHAROPOLYSPORA-ERYTHRAEA; 2 GLYCOSYLTRANSFERASES; BETA-GLUCOSYLTRANSFERASE; CATALYTIC MECHANISM; CONJUGAL TRANSFER; IDENTIFICATION;
Keywords:
chimera; glycosyltransferase; Streptomyces; D-olivose; L-rhodinose;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
57
Recensione:
Indirizzi per estratti:
Indirizzo: Bechthold, A Univ Freiburg, Stefan Meier Str 19, D-79104 Freiburg, GermanyUniv Freiburg Stefan Meier Str 19 Freiburg Germany D-79104 y
Citazione:
D. Hoffmeister et al., "Two sequence elements of glycosyltransferases involved in urdamycin biosynthesis are responsible for substrate specificity and enzymatic activity", CHEM BIOL, 8(6), 2001, pp. 557-567

Abstract

Background: Two deoxysugar glycosyltransferases (GTs), UrdGT1b and UrdGT1c, involved in urdamycin biosynthesis share 91% identical amino acids. However, the two GTs show different specificities for both nucleotide sugar and acceptor substrate. Generally, it is proposed that GTs are two-domain proteins with a nucleotide binding domain and an acceptor substrate site with the catalytic center in an interface cleft between these domains. Our work aimed at finding out the region responsible for determination of substrate specificities of these two urdamycin GTs. Results: A series of 10 chimeric GT genes were constructed consisting of differently sized and positioned portions of urdGT1b and urdCT1c. Gene expression experiments in host strains Streptomyces fradiae Ax and XTC show thatnine of 10 chimeric GTs are still functional, with either UrdGT1b- or UrdGT1c-like activity. A 31 amino acid region (aa 52-82) located close to the N-terminus of these enzymes, which differs in 18 residues, was identified tocontrol both sugar donor and acceptor substrate specificity. Only one chimeric gene product of the 10 was not functional. Targeted stepwise alterations of glycine 226 (G226R, G226S, G226SR) were made to reintroduce residues conserved among streptomycete GTs. Alterations G226S and G226R restored a weak activity, whereas G226SR showed an activity comparable with other functional chimeras. Conclusions: A nucleotide sugar binding motif is present in the C-terminalmoiety of UrdGT1b and UrdGT1c from S. fradiae. We could demonstrate that it is an N-terminal section that determines specificity for the nucleotide sugar and also the acceptor substrate. This finding directs the way towards engineering this class of streptomycete enzymes for antibiotic derivatization applications. Amino acids 226 and 227, located outside the putative substrate binding site, might be part of a larger protein structure, perhaps a solvent channel to the catalytic center. Therefore, they could play a role in substrate accessibility to it. (C) 2001 Elsevier Science Ltd. All rightsreserved.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 04/07/20 alle ore 18:30:14