A critical role for the histidine residues in the catalytic function of acyl-CoA:cholesterol acyltransferase catalysis: evidence for catalytic difference between ACAT1 and ACAT2

FEBS Letters
Sojin AnTae-Sook Jeong

Abstract

To investigate a role for histidine residues in the expression of normal acyl-CoA:cholesterol acyltransferase (ACAT) activity, the histidine residues located at five different positions in two isoenzymes were substituted by alanine, based on the sequence homology between ACAT1 and ACAT2. Among the 10 mutants generated by baculovirus expression technology, H386A-ACAT1, H460A-ACAT1, H360A-ACAT2, and H399A-ACAT2 lost their enzymatic activity completely. A reduction in catalytic activity is unlikely to result from structural changes in the substrate-binding pocket, because their substrate-binding affinities were normal. However, the enzymatic activity of H386A-ACAT1 was restored to <37% of the level of the wild-type activity when cholesterol was replaced by 25-hydroxycholesterol as substrate. H527A-ACAT1 and H501A-ACAT2, termed carboxyl end mutants, exhibit activities of approximately 96% and approximately 75% of that of the wild-type. Interestingly, H425A-ACAT1 showed 59% of the wild-type activity, in contrast to its equivalent mutant, H399A-ACAT2. These results demonstrate that the histidine residues located at the active site are very crucial both for the catalytic activity of the enzyme and for distinguishing ACAT1 from ACAT2 w...Continue Reading

References

Jan 1, 1997·Annual Review of Biochemistry·T Y ChangD Cheng
Oct 3, 1998·The Journal of Biological Chemistry·P OelkersS L Sturley
Apr 8, 1999·Progress in Lipid Research·A Jonas
Jun 10, 2000·The Journal of Biological Chemistry·C C ChangT Y Chang
Mar 30, 2001·The Journal of Biological Chemistry·D Armstrong, P G Strange
Sep 19, 2003·Biochemical and Biophysical Research Communications·Kyung-Hyun ChoTae-Sook Jeong
May 6, 2004·Bioorganic & Medicinal Chemistry Letters·Tae-Sook JeongWoo Song Lee
Mar 23, 2005·Biochemistry·Ryan WoodyerWilfred A van der Donk
Jun 16, 2005·The FEBS Journal·Enrico G FunhoffBruce A Averill

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Citations

Sep 4, 2012·Toxicological Sciences : an Official Journal of the Society of Toxicology·Alison H HarrillPaul B Watkins
Jan 15, 2009·American Journal of Physiology. Endocrinology and Metabolism·Ta-Yuan ChangYasuomi Urano
May 16, 2008·Journal of Lipid Research·Akash DasLawrence L Rudel
Dec 13, 2006·Bioorganic & Medicinal Chemistry Letters·Sojin AnWoo Song Lee
Aug 31, 2021·Irish Journal of Medical Science·Xin-Chun WangLi-Feng Feng

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