@article{mbs:/content/journal/micro/10.1099/mic.0.27467-0, author = "Kimura, Keitarou and Tran, Lam-Son Phan and Uchida, Ikuo and Itoh, Yoshifumi", title = "Characterization of Bacillus subtilisγ-glutamyltransferase and its involvement in the degradation of capsule poly-γ-glutamate", journal= "Microbiology", year = "2004", volume = "150", number = "12", pages = "4115-4123", doi = "https://doi.org/10.1099/mic.0.27467-0", url = "https://www.microbiologyresearch.org/content/journal/micro/10.1099/mic.0.27467-0", publisher = "Microbiology Society", issn = "1465-2080", type = "Journal Article", keywords = "γGNA, γ-glutamyl-p-nitroanilide", keywords = "γPGA, poly(γ-glutamic acid)", keywords = "GGT, γ-glutamyltransferase", 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.", }