Catalogo Articoli (Spogli Riviste)

OPAC HELP

Titolo:
THIAMINASE-I (42-KDA) HETEROGENEITY, SEQUENCE REFINEMENT, AND ACTIVE-SITE LOCATION FROM HIGH-RESOLUTION TANDEM MASS-SPECTROMETRY
Autore:
KELLEHER NL; COSTELLO CA; BEGLEY TP; MCLAFFERTY FW;
Indirizzi:
CORNELL UNIV,BAKER LAB,DEPT CHEM ITHACA NY 14853 CORNELL UNIV,BAKER LAB,DEPT CHEM ITHACA NY 14853
Titolo Testata:
Journal of the American Society for Mass Spectrometry
fascicolo: 10, volume: 6, anno: 1995,
pagine: 981 - 984
SICI:
1044-0305(1995)6:10<981:T(HSRA>2.0.ZU;2-6
Fonte:
ISI
Lingua:
ENG
Tipo documento:
Note
Natura:
Periodico
Settore Disciplinare:
Science Citation Index Expanded
Science Citation Index Expanded
Science Citation Index Expanded
Citazioni:
16
Recensione:
Indirizzi per estratti:
Citazione:
N.L. Kelleher et al., "THIAMINASE-I (42-KDA) HETEROGENEITY, SEQUENCE REFINEMENT, AND ACTIVE-SITE LOCATION FROM HIGH-RESOLUTION TANDEM MASS-SPECTROMETRY", Journal of the American Society for Mass Spectrometry, 6(10), 1995, pp. 981-984

Abstract

Thiaminase I(E.C. 2.5.1.2) from Bacillus thiaminolyticus catalyzes the degradation of thiamin (vitamin B-1). Unexpected mass heterogeneity (MW 42,127, 42,197, and 42,254; 1:2:1) in recombinant thiaminase I from Escherichia coli was detected by electrospray ionization Fourier-transform mass spectrometry, resolving power 7 x 10(4). Nozzle-skimmer fragmentation data reveal an extra Ala (+ 71.02; 71.04 = theory) and GlyAla (+ 128.04; 128.06 = theory) on the N-terminus, in addition to the fully processed enzyme. However, the fragment ion masses were consistent only with this sequence through 330 N-terminal residues; resequencing of the last 150 bps of the thiaminase I gene yields a sequence consistent with the molecular weight values and all 61 fragment ion masses. Covalently labeling the active site with a 108-Da pyrimidine moiety via mechanism-based inhibition produces a corresponding molecular weight increase in all three thiaminase I components, which indicates thatthey are all enzymatically active. Inspection of the fragment ions that do and do not increase by 108 Da indicates that the active site nucleophile is located between pro(79) and Thr(177) in the 379 amino acidenzyme.

ASDD Area Sistemi Dipartimentali e Documentali, Università di Bologna, Catalogo delle riviste ed altri periodici
Documento generato il 14/07/20 alle ore 19:49:50