Microbial production and chemical transformation of poly-γ-glutamate.
Bottom Line: The occurrence of multiple carboxyl residues in PGA likely plays a role in its relative unsuitability for the development of bio-nylon plastics and thus, establishment of an efficient PGA-reforming strategy is of great importance.Aside from the potential applications of PGA proposed to date, a new technique for chemical transformation of PGA is also discussed.Finally, some techniques for PGA and its derivatives in advanced material technology are presented.
Affiliation: Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Nankoku, Kochi, 783-8502, Japan.Show MeSH
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Mentions: As expected, current research supports the idea that DL-PGA synthetase is a membrane-associated modular protein complex (viz., PgsBCAE) with a Rossmann-type amide ligase-like PgsB component (Fig. 4; Ashiuchi et al., 1999; 2001b; Urushibata et al., 2002). Research has also been published on the operon organization and molecular machinery involved in D-PGA synthesis in B. anthracis (Candela and Fouet, 2006), the L-rich PGA synthesis carried out by B. megaterium (DDBJ accession no., AB571872), the DL-PGA synthesis by S. epidermidis (Kocianova et al., 2005) and the PGA synthesis by Fusobacterium nucleatum (Candela et al., 2009). All are homologous to the DL-PGA synthesis carried out by B. subtilis (Fig. 5). These bacteria possess the responsible genes for d-glutamate synthesis (Kunst et al., 1997; Kapatral et al., 2002; Read et al., 2003; Zhang et al., 2003; Eppinger et al., 2011) and generally demonstrate the associated enzyme activities in varying amounts (Table 1). In contrast, N. aegyptiaca, which is capable of producing long-chain L-PGA, does not contain any pathways for d-glutamate supply (Ashiuchi et al., 2013b). B. halodurans has the machinery to potentially participate in d-glutamate synthesis similar to other bacilli (Takami et al., 2000), though it can produce L-PGA in the absence of d-glutamyl residues. It is noteworthy that neither the pgs nor cap operon is found in the B. halodurans genome (Takami et al., 2000), because this strongly implies the participation of an unidentified system: for example, novel L-PGA synthetase(s) with an ATP-grasp domain.
Affiliation: Agricultural Science, Graduate School of Integrated Arts and Sciences, Kochi University, Nankoku, Kochi, 783-8502, Japan.