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Titolo:
UNEXPECTED SEQUENCE SIMILARITY BETWEEN NUCLEOSIDASES AND PHOSPHORIBOSYLTRANSFERASES OF DIFFERENT SPECIFICITY
Autore:
MUSHEGIAN AR; KOONIN EV;
Indirizzi:
NIH,NATL LIB MED,NATL CTR BIOTECHNOL INFORMAT,BLDG 10 BETHESDA MD 20894 NIH,NATL LIB MED,NATL CTR BIOTECHNOL INFORMAT BETHESDA MD 20894 UNIV KENTUCKY,DEPT PLANT PATHOL LEXINGTON KY 40546
Titolo Testata:
Protein science
fascicolo: 7, volume: 3, anno: 1994,
pagine: 1081 - 1088
SICI:
0961-8368(1994)3:7<1081:USSBNA>2.0.ZU;2-7
Fonte:
ISI
Lingua:
ENG
Soggetto:
ACID SUBSTITUTION MATRICES; ESCHERICHIA-COLI; THYMIDINE PHOSPHORYLASE; 3-DIMENSIONAL STRUCTURE; AMP NUCLEOSIDASE; STORAGE PROTEIN; ATP-BINDING; EXPRESSION; GENE; OPERON;
Keywords:
NUCLEOSIDASES; PHOSPHORIBOSYLTRANSFERASES; SEQUENCE SIMILARITY;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Citazioni:
45
Recensione:
Indirizzi per estratti:
Citazione:
A.R. Mushegian e E.V. Koonin, "UNEXPECTED SEQUENCE SIMILARITY BETWEEN NUCLEOSIDASES AND PHOSPHORIBOSYLTRANSFERASES OF DIFFERENT SPECIFICITY", Protein science, 3(7), 1994, pp. 1081-1088

Abstract

Amino acid sequences of enzymes that catalyze hydrolysis or phosphorolysis of the N-glycosidic bond in nucleosides and nucleotides (nucleosidases and phosphoribosyltransferases) were explored using computer methods for database similarity search and multiple alignment. Two new families, each including bacterial and eukaryotic enzymes, were identified. Family I consists of Escherichia coli AMP hydrolase (Amn), uridine phosphorylase (Udp), purine phosphorylase (DeoD), uncharacterized proteins from E. coli and Bacteroides uniformis, and, unexpectedly, a group of plant stress-inducible proteins. It is hypothesized that these plant proteins have evolved from nucleosidases and may possess nucleosidase activity. The proteins in this new family contain 3 conserved motifs, one of which was found also in eukaryotic purine nucleosidases, where it corresponds to the nucleoside-binding site. Family II is comprised of bacterial and eukaryotic thymidine phosphorylases and anthranilate phosphoribosyltransferases, the relationship between which has not been suspected previously. Based on the known tertiary structure ofE. coli thymidine phosphorylase, structural interpretation was given to the sequence conservation in this family. The highest conservation is observed in the N-terminal alpha-helical domain, whose exact function is not known. Parts of the conserved active site of thymidine phosphorylases and anthranilate phosphoribosyltransferases were delineated. A motif in the putative phosphate-binding site is conserved in familyII and in other phosphoribosyltransferases. Our analysis suggests that certain enzymes of very similar specificity, e.g., uridine and thymidine phosphorylases, could have evolved independently. In contrast, enzymes catalyzing such different reactions as AMP hydrolysis and uridine phosphorolysis or thymidine phosphorolysis and phosphoribosyl anthranilate synthesis are likely to have evolved from common ancestors.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 25/09/20 alle ore 05:27:11