LRAT domain
IPR007053
Definition
This domain (LRAT domain) is found in a variety of proteins, including lecithin retinol acyltransferase (LRAT), HRAS-like suppressors (HRASLS1-5) and proteins FAM84A and FAM84B. Acyltransferase LRAT is the main enzyme that catalyzes vitamin A esterification PMID:16174770. HRASLS enzymes are also referred to as LRAT-like proteins because of their sequence homology to LRAT PMID:22605381. The basic structural motif of the LRAT domain is composed of a four-strand antiparallel β-sheet and three α-helices. The longest α-helix (alpha3) is packed against the β-sheet, and the two other shorter α-helices are located on the sides. A highly conserved catalytic Cys, identified as the acylation site, is located near the N terminus of alpha3. This arrangement defines the active site location, which is embedded into a well defined groove formed by the extended loops between beta1-beta2, beta3-beta4, and the N terminus of the alpha3 helix. The side chain of the Cys is packed against a β-sheet core of the domain, placing it in close proximity to a conserved His from the beta2 strand. The β-sheet is spread open on one end allowing formation of a hydrogen bond between the His and the Cys. The third polar residue in this catalytic triad is a polar residue in the neighboring beta3 strand. The Cys residue was shown to act as a nucleophile and form a covalent thiol-acyl intermediate in the catalytic process [[cite:PMID:22605381], [cite:PMID:22923616], [cite:PMID:25871522]].
8 human proteins with this domain
Each is a reviewed human protein in the Seroatlas serome and a potential autoantibody target; this domain groups them into one antibody-relevant category. Every entry links to its own record.
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