Type III Pyridoxal 5-phosphate (PLP)-Dependent Enzyme yhfX
This subfamily is composed of the uncharacterized protein yhfX from Escherichia coli K-12 and similar bacterial proteins. These proteins are homologous to bacterial alanine racemases (AR), which are fold type III PLP-dependent enzymes containing an N-terminal PLP-binding TIM-barrel domain and a C-terminal beta-sandwich domain. AR exists as homodimers with active sites that lie at the interface between the TIM barrel domain of one subunit and the beta-sandwich domain of the other subunit. It catalyzes the interconversion between L- and D-alanine, which is an essential component of the peptidoglycan layer of bacterial cell walls. Members of this subfamily may act as PLP-dependent enzymes.