Abstract
Arginine kinase (AK) is a key enzyme for energetic balance in invertebrates. Although AK is a well-studied system that provides fast energy to invertebrates using the phosphagen phospho-arginine, the structural details on the AK-arginine binary complex interaction remain unclear. Herein, we determined two crystal structures of the Pacific whiteleg shrimp (Litopenaeus vannamei) arginine kinase, one in binary complex with arginine (LvAK-Arg) and a ternary transition state analog complex (TSAC). We found that the arginine guanidinium group makes ionic contacts with Glu225, Cys271 and a network of ordered water molecules. On the zwitterionic side of the amino acid, the backbone amide nitrogens of Gly64 and Val65 coordinate the arginine carboxylate. Glu314, one of proposed acid-base catalytic residues, did not interact with arginine in the binary complex. This residue is located in the flexible loop 310-320 that covers the active site and only stabilizes in the LvAK-TSAC. This is the first binary complex crystal structure of a guanidine kinase in complex with the guanidine substrate and could give insights into the nature of the early steps of phosphagen biosynthesis.
Original language | English |
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Pages (from-to) | 511-518 |
Number of pages | 8 |
Journal | Journal of Bioenergetics and Biomembranes |
Volume | 45 |
Issue number | 6 |
DOIs | |
State | Published - Dec 2013 |
Bibliographical note
Funding Information:Acknowledgements R.R. Sotelo-Mundo and M.F. Criscitiello thank grant 2011–050 from the Texas A&M-CONACYT (Mexico’s National Research Council for Science and Technology) Collaborative Grant Program and CONACYT grants CB-2009-131859 and E0007-2011-01-179940 and COFUPRO RNIIPA-2012-024 grant. A.A. López-Zavala and J.S. Carrasco-Miranda thank CONACYT for their doctoral fellowship. Dr. Sugich-Miranda was a postdoctoral fellow at Dr. Sotelo’s Lab during this investigation, supported by Universidad de Sonora. We thanks Dr. Vivian Stojanoff and the staff at BNL NSLS beamline X6A for data-collection facilities. Beamline X6A is funded by NIGMS (GM-0080) and the US Department of Energy (No. DE-AC02-98CH10886). Dr. Sotelo-Mundo thanks support for a sabbatical leave at DIPM, Universidad de Sonora.
Keywords
- Arginine kinase
- Binary complex
- Crystal structure
- Litopenaeus vannamei
- Phosphagen
- Shrimp