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Titolo:
Hyaluronan binding and degradation by Streptococcus agalactiae hyaluronatelyase
Autore:
Li, SL; Jedrzejas, MJ;
Indirizzi:
Univ Alabama, Dept Microbiol, Birmingham, AL 35294 USA Univ Alabama Birmingham AL USA 35294 Microbiol, Birmingham, AL 35294 USA
Titolo Testata:
JOURNAL OF BIOLOGICAL CHEMISTRY
fascicolo: 44, volume: 276, anno: 2001,
pagine: 41407 - 41416
SICI:
0021-9258(20011102)276:44<41407:HBADBS>2.0.ZU;2-S
Fonte:
ISI
Lingua:
ENG
Soggetto:
GROUP-B STREPTOCOCCUS; ACTION PATTERN; PNEUMONIAE; RESOLUTION; EXPRESSION; GENE; SPECIFICITY; ASSOCIATION; INFECTIONS; VIRULENCE;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
43
Recensione:
Indirizzi per estratti:
Indirizzo: Jedrzejas, MJ Childrens Hosp Oakland, Res Inst, 5700 Martin Luther King JrWay, Oakland,CA 94609 USA Childrens Hosp Oakland 5700 Martin Luther King Jr Way Oakland CA USA 94609
Citazione:
S.L. Li e M.J. Jedrzejas, "Hyaluronan binding and degradation by Streptococcus agalactiae hyaluronatelyase", J BIOL CHEM, 276(44), 2001, pp. 41407-41416

Abstract

Streptococcus agalactiae hyaluronate lyase is a virulence factor that helps this pathogen to break through the biophysical barrier of the host tissues by the enzymatic degradation of hyaluronan and certain chondroitin sulfates at beta -1,4 glycosidic linkages. Crystal structures of the native enzyme and the enzyme-product complex were determined at 2.1- and 2.2-Angstrom resolutions, respectively. An elongated cleft transversing the middle of themolecule has been identified as the substrate-binding place. Two product molecules of hyaluronan degradation were observed bound to the cleft. The enzyme catalytic site was identified to comprise three residues: His(479), Tyr(488), and Asn(429). The highly positively charged cleft facilitates the binding of the negatively charged polymeric substrate chain. The matching between the aromatic patch of the enzyme and the hydrophobic patch of the substrate chain anchors the substrate chain into degradation position. A pair of proton exchanges between the enzyme and the substrate results in the cleavage of the beta -1,4 glycosidic linkage of the substrate chain and the unsaturation of the product. Phe(423) likely determines the size of the product at the product release side of the catalytic region. Hyaluronan chain isprocessively degraded from the reducing end toward the nonreducing end. The unsulfated or 6-sulfated regions of chondroitin sulfate can also be degraded in the same manner as hyaluronan.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 28/09/20 alle ore 15:32:34