Characterization of Bacillus subtilisγ-glutamyltransferase and its involvement in the degradation of capsule poly-γ-glutamate
Kimura, Keitarou and Tran, Lam-Son Phan and Uchida, Ikuo and Itoh, Yoshifumi,, 150, 4115-4123 (2004),
doi = https://doi.org/10.1099/mic.0.27467-0,
publicationName = Microbiology Society,
issn = 1350-0872,
abstract= During early stationary phase, Bacillus subtilis NAFM5 produces capsular poly(γ-glutamic acid) (γPGA, 2×106 Da), which contains d- and l-glutamate, and then degrades it during late stationary phase. The γ-glutamyltransferase (EC 2.3.2.2; GGT) of this strain successively hydrolysed γPGA from the amino-terminal end, to yield both d- and l-glutamate. This enzyme was specifically synthesized during the stationary phase through transcriptional activation of the corresponding ggt gene by the ComQXPA quorum-sensing system. A ggt knockout mutant degraded γPGA into 1×105 Da fragments, but not any further, indicating that the capsule γPGA is first internally degraded by an endo-type of γPGA hydrolase into 1×105 Da intermediates, then externally into glutamates via GGT. Due to its inability to generate the glutamates from the capsule, the ggt mutant sporulated more frequently than the wild-type strain. The results show that B. subtilis GGT has a powerful exo-γ-glutamyl hydrolase activity that participates in capsule γPGA degradation to supply stationary-phase cells with constituent glutamates.,
language=,
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