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Structural studies on Δ 3 ‐Δ 2 ‐enoyl‐CoA isomerase: the variable mode of assembly of the trimeric disks of the crotonase superfamily
Author(s) -
Mursula Anu M.,
Hiltunen J.Kalervo,
Wierenga Rik K.
Publication year - 2004
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/s0014-5793(03)01450-9
Subject(s) - superfamily , trimer , ras superfamily , isomerase , stereochemistry , chemistry , random hexamer , yeast , substrate (aquarium) , crystallography , crystal structure , enzyme , protein structure , biochemistry , dimer , biology , gene , ecology , organic chemistry , gtp'
Subunits of the enzymes in the crotonase superfamily form tight trimeric disks. In most members of this protein superfamily these disks assemble further into hexamers. Here we report on the 2.1 Å structure of a tight hexameric crystal form of the yeast peroxisomal Δ 3 ‐Δ 2 ‐enoyl‐CoA isomerase (Eci1p). A comparison of this structure to a previously solved crystal form of Eci1p and other structures of this superfamily shows that there is much variability with respect to the relative distance between the disks and their relative orientations. In particular helices H2 and H9 are involved in the inter‐trimer contacts and there are considerable structural differences in these helices in this superfamily. Helices H2 and H9 are near the catalytic cavity and it is postulated that the observed structural variability of these helices, stabilized by the different modes of assembly, has allowed the evolution of the wide range of substrate and catalytic specificity within this enzyme superfamily.