1dr8
From Proteopedia
STRUCTURE OF MODIFIED 3-ISOPROPYLMALATE DEHYDROGENASE AT THE C-TERMINUS, HD177
Overview
Thermal stability of the Thermus thermophilus isopropylmalate dehydrogenase enzyme was substantially lost upon the deletion of three residues from the C-terminus. However, the stability was partly recovered by the addition of two, four and seven amino acid residues (called HD177, HD708 and HD711, respectively) to the C-terminal region of the truncated enzyme. Three structures of these mutant enzymes were determined by an X-ray diffraction method. All protein crystals belong to space group P2(1) and their structures were solved by a standard molecular replacement method where the original dimer structure of the A172L mutant was used as a search model. Thermal stability of these mutant enzymes is discussed based on the 3D structure with special attention to the width of the active-site groove and the minor groove, distortion of beta-sheet pillar structure and size of cavity in the domain-domain interface around the C-terminus. Our previous studies revealed that the thermal stability of isopropylmalate dehydrogenase increases when the active-site cleft is closed (the closed form). In the present study it is shown that the active-site cleft can be regulated by open-close movement of the minor groove located at the opposite side to the active-site groove on the same subunit, through a paperclip-like motion.
About this Structure
1DR8 is a Single protein structure of sequence from Thermus thermophilus. Full crystallographic information is available from OCA.
Reference
Crystal structures of 3-isopropylmalate dehydrogenases with mutations at the C-terminus: crystallographic analyses of structure-stability relationships., Nurachman Z, Akanuma S, Sato T, Oshima T, Tanaka N, Protein Eng. 2000 Apr;13(4):253-8. PMID:10810156 Page seeded by OCA on Fri May 2 14:11:04 2008
