pfam16576: HlyD_D23 (This model is not part of the current CDD release)
Barrel-sandwich domain of CusB or HlyD membrane-fusion
This entry represents a domain comprising the combined domains 2 and 3 of the membrane-fusion proteins CusB and HlyD. It is formed by a barrel-sandwich domain which is inserted in a RIFT-like domain. The barrel-sandwich domain, itself, contains an insert of a three-helical bundle subdomain. CusB and HlyD proteins are membrane fusion proteins of the CusCFBA copper efflux system in E.coli and related bacteria. The whole molecule hinges between D2 and D3. Efflux systems of this resistance-nodulation-division group - RND - have been developed to excrete poisonous metal ions, and in E.coli the only one that deals with silver and copper is the CusA transporter. The transporter CusA works in conjunction with a periplasmic component that is a membrane fusion protein, eg CusB, and an outer-membrane channel component CusC in a CusABC complex driven by import of protons.
Jiyao W et al.(2023). "The conserved domain database in 2023.",