A conservative amino acid substitution alters the regiospecificity of CYP94A2, a fatty acid hydroxylase from the plant Vicia sativa

Citation
Ra. Kahn et al., A conservative amino acid substitution alters the regiospecificity of CYP94A2, a fatty acid hydroxylase from the plant Vicia sativa, ARCH BIOCH, 391(2), 2001, pp. 180-187
Citations number
38
Categorie Soggetti
Biochemistry & Biophysics
Journal title
ARCHIVES OF BIOCHEMISTRY AND BIOPHYSICS
ISSN journal
00039861 → ACNP
Volume
391
Issue
2
Year of publication
2001
Pages
180 - 187
Database
ISI
SICI code
0003-9861(20010715)391:2<180:ACAASA>2.0.ZU;2-K
Abstract
Fatty acid omega -hydroxylation is involved in the biosynthesis of the plan t cuticle, formation of plant defense signaling molecules, and possibly in the rapid catabolism of free fatty acids liberated under stress conditions. CYP94A2 is a cytochrome P450-dependent medium-chain fatty acid hydroxylase that was recently isolated from Vicia sativa, Contrary to CYP94A1 and CYP8 6A1, two other fatty acid hydroxylases previously characterized in V. sativ a and Arabidopsis thaliana, CYP94A2 is not a strict omega -hydroxylase, but exhibits chain-length-dependent regioselectivity of oxidative attack. Sequ ence alignments of CYP94A2 with CYP94A1 and molecular modeling studies sugg ested that F494, located in SRS-B (substrate recognition site) was involved in substrate recognition and positioning. Indeed, a conservative amino aci d substitution at that position markedly altered the regiospecificity of CY P94A2. The observed shift from omega toward omega -1 hydroxylation was prom inent with lauric acid as substrate and declined with increasing fatty acid chain length. (C) 2001 Academic Press.