C-terminal end and aminoacid Lys48 in HMG-CoA lyase are involved in substrate binding and enzyme activity.

Mol Genet Metab 2007 Jun 24;91(2):120-7. Epub 2007 Apr 24.

Department of Biochemistry and Molecular Biology, School of Health Sciences, Universitat Internacional de Catalunya, E-08195 Sant Cugat, Barcelona, Spain.

3-hydroxy-3-methylglutaryl-CoA (HMG-CoA) lyase adopts a (betaalpha)(8) TIM barrel structure with an additional beta9, alpha11 and alpha12 helices. Location of HMG part of the substrate has been suggested but the binding mode for the CoA moiety remains to be resolved. As mutation F305 fs(-2), which involves the last 21 residues of the protein, and mutation K48N caused 3-hydroxy-3-methylglutaric aciduria in two patients, we examined the role of the C-terminal end and Lys(48) in enzyme activity. Expression studies of various C-terminal-end-deleted and K48N-mutated proteins revealed that residues 311-313 (localized in the loop between alpha11 and alpha12 helices) and Lys(48) are essential for enzyme activity. An in silico docking model locating HMG-CoA on the surface of the enzyme implicates Asn(311) and Lys(313) in substrate binding by establishing multiple polar contacts with phosphate and ribose groups of adenosine, and Lys(48) by contacting the carboxyl group of the panthotenic acid moiety.

Download full-text PDF

Source
http://dx.doi.org/10.1016/j.ymgme.2007.03.007DOI Listing
June 2007
12 Reads

Publication Analysis

Top Keywords

enzyme activity
12
alpha12 helices
8
substrate binding
8
alpha11 alpha12
8
hmg-coa lyase
8
studies c-terminal-end-deleted
4
loop alpha11
4
expression studies
4
activity expression
4
c-terminal-end-deleted k48n-mutated
4
k48n-mutated proteins
4
residues 311-313
4
311-313 localized
4
proteins revealed
4
localized loop
4
revealed residues
4
c-terminal lys48
4
protein mutation
4
mutation k48n
4
residues protein
4

Similar Publications