The MBOAT (membrane bound O-acyl transferase) family of membrane proteins is a family of various acyltransferase enzymes. All family members contain multiple transmembrane domains and most carry two conserved residues, a conservedhistidine (His) embedded in a hydrophobic stretch of residues and an asparagine (Asn) or histidine within a more hydrophilic region some 30-50 residues upstream.[1]
The structure for one MBOAT protein, DltB from Streptococcus thermophilus (Q5M4V4), has been solved. DltB performs D-alanylation of cell-wall teichoic acid. It contains a ring of 11 transmembrane helices surrounding a tunnel that goes through the biological membrane. The tunnel connects to a partner, DltC, which carries the D-alanine to the conserved histidine residue of DltB MBOAT located at the bottom of the funnel.[4] A computational model of human ghrelin O-acyltransferase (GOAT) (Q96T53) revealed a transmembrane channel that facilitates octanoylation of the peptide hormone ghrelin.[5] DltB and GOAT share structural similarities in their homologous regions, suggesting a common core fold for MBOAT family members.
^Hofmann K (March 2000). "A superfamily of membrane-bound O-acyltransferases with implications for wnt signaling". Trends Biochem. Sci. 25 (3): 111–2. doi:10.1016/s0968-0004(99)01539-x. PMID10694878.