3VBA

Crystal structure of methanogen 3-isopropylmalate isomerase small subunit

Summary for 3VBA

• Entry DOI: 10.2210/pdb3vba/pdb
• Descriptor: Isopropylmalate/citramalate isomerase small subunit (2 entities in total)
• Functional Keywords: lyase, leud, cytosol
• Biological source: Methanocaldococcus jannaschii
• Total number of polymer chains: 6
• Total formula weight: 116829.27

Authors

Hwang, K.Y.,Lee, E.H. (deposition date: 2012-01-02, release date: 2012-11-14, Last modification date: 2024-03-20)

Primary citation

Lee, E.H.,Cho, Y.W.,Hwang, K.Y.
Crystal structure of LeuD from Methanococcus jannaschii.
Biochem.Biophys.Res.Commun., 419:160-164, 2012

PubMed Abstract: 3-Isopropylmalate/citramalate (IPM) isomerase catalyzes the second step in the leucine biosynthesis pathway. IPM isomerase from Methanococcus jannaschii is a complex protein consisting of a large (MjLeuC) and a small subunit (MjLeuD). It has broad substrate specificity, unlike other bacterial IPM isomerases. In order to understand the reasons for this broad substrate specificity, we determined the crystal structure of MjLeuD at a resolution of 2.0 Å. The asymmetric unit contained 6 molecules of LeuD, including three homodimers. The overall structure had a β/β/α sandwich-fold consisting of 8 α-helices and 7 β-strands. The C-terminal helix, which is important in homodimer formation, showed conformational differences between two homodimer forms of MjLeuD. In addition, we identified a hydrophobic residue (Val28) near the substrate recognition region that may explain the broad substrate specificity of IPM isomerase. Therefore, we suggest that LeuD proteins can be divided into 2 subfamilies, LeuD subfamilies 1 and 2, which show differences in overall structure and in the substrate recognition region.

PubMed: 22326391
DOI: 10.1016/j.bbrc.2012.01.125

Experimental method

X-RAY DIFFRACTION (2 Å)