BACKGROUND: Metabolic variations exist between the @entity1853 salvage pathway of @entity1 and a number of plants and microbial pathogens. @entity68606 (MTR) kinase is a key enzyme required for @entity1853 salvage in plants and many bacteria. The absence of a @entity1 homolog suggests that MTR kinase is a good target for the design of specific herbicides or antibiotics. RESULTS: The structure of @entity958 MTR kinase co-crystallized with ATPgammaS and MTR has been determined at 1.9 A resolution. The structure is similar to @entity3881 MTR kinase and has the same protein kinase fold observed in other evolutionarily related protein kinase-like phosphotransferases. The active site is comparable between the two enzymes with the DXE-motif coordinating the @entity377 -Mg, the D238 of the HGD catalytic loop polarizing the MTR O1 @entity26 , and the RR-motif interacting with the substrate MTR. Unlike its bacterial homolog, however, the @entity4022 -rich loop (G-loop) of A. thaliana MTR kinase has an extended conformation, which shields most of the active site from solvent, a feature that resembles eukaryotic protein kinases more than the bacterial enzyme. The G- and W-loops of A. thaliana and @entity3881 MTR kinase adopt different conformations despite high sequence similarity. The ATPgammaS analog was hydrolyzed during the co-crystallization procedure, resulting in @entity857 in the active site. This suggests that the A. thaliana enzyme, like its bacterial homolog, may have significant ATPase activity in the absence of MTR. CONCLUSION: The structure of A. thaliana MTR kinase provides a template for structure-based design of agrochemicals, particularly herbicides whose effectiveness could be regulated by nutrient levels. Features of the MTR binding site offer an opportunity for a simple organic salt of an MTR analog to specifically inhibit MTR kinase.

Structure of XXXX @entity68606 kinase reveals a more occluded active site than its bacterial homolog.

@entity1 :: ('9606', 'Species') :: ['mammalian', 'humans'] @entity958 :: ('3702', 'Species') :: ['Arabidopsis thaliana'] @entity26 :: ('MESH:D010100', 'Chemical') :: ['oxygen'] @entity4022 :: ('MESH:C066286', 'Chemical') :: ['Gly'] @entity377 :: ('CHEBI:36976', 'Chemical') :: ['nucleotide'] @entity1853 :: ('MESH:D008715', 'Chemical') :: ['methionine'] @entity857 :: ('MESH:D000244', 'Chemical') :: ['ADP'] @entity3881 :: ('1423', 'Species') :: ['B. subtilis'] @entity68606 :: ('MESH:C001955', 'Chemical') :: ['5-Methylthioribose']
@entity958 :: (3702,Species) :: ['Arabidopsis thaliana']
