Crystal structure of shrimp arginine kinase in binary complex with arginine-a molecular view of the phosphagen precursor binding to the enzyme.
J Bioenerg Biomembr
; 45(6): 511-8, 2013 Dec.
Article
em En
| MEDLINE
| ID: mdl-23873077
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.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Assunto principal:
Arginina
/
Arginina Quinase
/
Penaeidae
Limite:
Animals
Idioma:
En
Revista:
J Bioenerg Biomembr
Ano de publicação:
2013
Tipo de documento:
Article
País de afiliação:
México
País de publicação:
Estados Unidos