Naslov
Active site titration of gramicidin S synthetase 2: evidence for misactivation and editing in non- ribosomal peptide biosynthesis

Autori
Kittelberger, Reinhold ; Pavela-Vrančič, Maja ; von Dohren, Hans

Izvornik
FEBS letters (0014-5793) 461 (1999), 3; 145-148

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
multienzyme ; peptide synthetase ; gramicidin S synthetase 2 ; aminoacyl adenylation ; misactivation ; editing

Sažetak
The catalytic competence of gramicidin S synthetase 2 (GS2) was determined by following the kinetics of PPi generation using active site titration measurements with [?-32P]ATP. The initial “burst“ of product formation can be correlated to the generation of the aminoacyl adenylate:enzyme complexes at the four amino acid activation domains and the subsequent aminoacylation of carrier domains, followed by a slow linear turnover of substrate due to breakdown of the intermediate. Simultaneous activation of all four amino acid substrates at saturating concentration displayed a consumption of 8.3 ATP/GS2. In the presence of single amino acids a binding stoichiometry higher than the anticipated 2 ATP per active site was obtained, implying misactivation at non-cognate domains. Breakdown of acyladenylate intermediates reflects a possible corrective mechanism by which the enzyme controlls the fidelity of product formation.

Izvorni jezik
Engleski

Znanstvena područja
Biologija

POVEZANOST RADA