InterPro

This family of proteins are found in a range of bacteria. The conserved region contains a conserved histidine and cysteine, suggesting that these proteins have an enzymatic activity. Several members of this family contain peptidoglycan binding domains. So these proteins may use peptidoglycan or a precursor as a substrate.

The molecular structure of YkuD protein shows this domain has a novel tertiary fold consisting of a beta-sandwich with two mixed sheets, one containing five strands and the other, six strands. The two beta-sheets form a cradle capped by an alpha-helix. This domain contains a putative catalytic site with a tetrad of invariant His123, Gly124, Cys139, and Arg141. The stereochemistry of this active site shows similarities to peptidotransferases and sortases, and suggests that the enzymes of this family may play an important role in cell wall biology. This family was formerly called the ErfK/YbiS/YcfS/YnhG family, but is now named after the first protein of known structure [PMID: 16287140, PMID: 16647082].