1r6x
From Proteopedia
The Crystal Structure of a Truncated Form of Yeast ATP Sulfurylase, Lacking the C-Terminal APS Kinase-like Domain, in complex with Sulfate
Overview
ATP sulfurylase catalyzes the first step in the activation of sulfate by transferring the adenylyl-moiety (AMP approximately ) of ATP to sulfate to form adenosine 5'-phosphosulfate (APS) and pyrophosphate (PP(i)). Subsequently, APS kinase mediates transfer of the gamma-phosphoryl group of ATP to APS to form 3'-phosphoadenosine 5'-phosphosulfate (PAPS) and ADP. The recently determined crystal structure of yeast ATP sulfurylase suggests that its C-terminal domain is structurally quite independent from the other domains, and not essential for catalytic activity. It seems, however, to dictate the oligomerization state of the protein. Here we show that truncation of this domain results in a monomeric enzyme with slightly enhanced catalytic efficiency. Structural alignment of the C-terminal domain indicated that it is extremely similar in its fold to APS kinase although not catalytically competent. While carrying out these structural and functional studies a surface groove was noted. Careful inspection and modeling revealed that the groove is sufficiently deep and wide, as well as properly positioned, to act as a substrate channel between the ATP sulfurylase and APS kinase-like domains of the enzyme.
About this Structure
1R6X is a Single protein structure of sequence from Saccharomyces cerevisiae. Full crystallographic information is available from OCA.
Reference
Structural and functional analysis of a truncated form of Saccharomyces cerevisiae ATP sulfurylase: C-terminal domain essential for oligomer formation but not for activity., Lalor DJ, Schnyder T, Saridakis V, Pilloff DE, Dong A, Tang H, Leyh TS, Pai EF, Protein Eng. 2003 Dec;16(12):1071-9. PMID:14983089 Page seeded by OCA on Sat May 3 07:09:25 2008
