1vrp
From Proteopedia
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The 2.1 Structure of T. californica Creatine Kinase Complexed with the Transition-State Analogue Complex, ADP-Mg 2+ /NO3-/Creatine
Overview
Creatine kinase (CK) catalyzes the reversible conversion of creatine and, ATP to phosphocreatine and ADP, thereby helping maintain energy, homeostasis in the cell. Here we report the first X-ray structure of CK, bound to a transition-state analogue complex (CK-TSAC). Cocrystallization, of the enzyme from Torpedo californica (TcCK) with ADP-Mg(2+), nitrate, and creatine yielded a homodimer, one monomer of which was liganded to a, TSAC complex while the second monomer was bound to ADP-Mg(2+) alone. The, structures of both monomers were determined to 2.1 A resolution. The, creatine is located with the guanidino nitrogen cis to the methyl group, positioned to perform in-line attack at the gamma-phosphate of ATP-Mg(2+), while the ADP-Mg(2+) is in a conformation similar to that found in the, TSAC-bound structure of the homologue arginine kinase (AK). Three ligands, to Mg(2+) are contributed by ADP and nitrate and three by ordered water, molecules. The most striking difference between the substrate-bound and, TSAC-bound structures is the movement of two loops, comprising residues, 60-70 and residues 323-332. In the TSAC-bound structure, both loops move, into the active site, resulting in the positioning of two hydrophobic, residues (one from each loop), Ile69 and Val325, near the methyl group of, creatine. This apparently provides a specificity pocket for optimal, creatine binding as this interaction is missing in the AK structure. In, addition, the active site of the transition-state analogue complex is, completely occluded from solvent, unlike the ADP-Mg(2+)-bound monomer and, the unliganded structures reported previously.
About this Structure
1VRP is a Single protein structure of sequence from Torpedo californica with MG, NO3, ADP and IOM as ligands. This structure superseeds the now removed PDB entry 1N16. Active as Creatine kinase, with EC number 2.7.3.2 Full crystallographic information is available from OCA.
Reference
The 2.1 A structure of Torpedo californica creatine kinase complexed with the ADP-Mg(2+)-NO(3)(-)-creatine transition-state analogue complex., Lahiri SD, Wang PF, Babbitt PC, McLeish MJ, Kenyon GL, Allen KN, Biochemistry. 2002 Nov 26;41(47):13861-7. PMID:12437342
Page seeded by OCA on Wed Nov 21 05:05:38 2007
