In:
Proceedings of the National Academy of Sciences, Proceedings of the National Academy of Sciences, Vol. 99, No. 6 ( 2002-03-19), p. 3458-3463
Abstract:
The histidine containing phospho carrier protein (HPr) kinase/phosphatase is involved in carbon catabolite repression, mainly in Gram-positive bacteria. It is a bifunctional enzyme that phosphorylates Ser-46-HPr in an ATP-dependent reaction and dephosphorylates P-Ser-46-HPr. X-ray analysis of the full-length crystalline enzyme from Staphylococcus xylosus at a resolution of 1.95 Å shows the enzyme to consist of two clearly separated domains that are assembled in a hexameric structure resembling a three-bladed propeller. The N-terminal domain has a βαβ fold similar to a segment from enzyme I of the sugar phosphotransferase system and to the uridyl-binding portion of MurF; it is structurally organized in three dimeric modules exposed to form the propeller blades. Two unexpected phosphate ions associated with highly conserved residues were found in the N-terminal dimeric interface. The C-terminal kinase domain is similar to that of the Lactobacillus casei enzyme and is assembled in six copies to form the compact central hub of the propeller. Beyond previously reported similarity with adenylate kinase, we suggest evolutionary relationship with phosphoenolpyruvate carboxykinase. In addition to a phosphate ion in the phosphate-binding loop of the kinase domain, we have identified a second phosphate-binding site that, by comparison with adenylate kinases, we believe accommodates a product/substrate phosphate, normally covalently linked to Ser-46 of HPr. Thus, we propose that our structure represents a product/substrate mimic of the kinase/phosphatase reaction.
Type of Medium:
Online Resource
ISSN:
0027-8424
,
1091-6490
DOI:
10.1073/pnas.052461499
Language:
English
Publisher:
Proceedings of the National Academy of Sciences
Publication Date:
2002
detail.hit.zdb_id:
209104-5
detail.hit.zdb_id:
1461794-8
SSG:
11
SSG:
12
