6ymu

Imidazole Glycerol Phosphate SynthaseImidazole Glycerol Phosphate Synthase

Structural highlights 6ymu is a 6 chain structure with sequence from Thermotoga maritima. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance. Method: X-ray diffraction, Resolution 2.11Å Ligands: Resources: FirstGlance, OCA, PDBe, RCSB, PDBsum, ProSAT Function HIS6_THEMA IGPS catalyzes the conversion of PRFAR and glutamine to IGP, AICAR and glutamate. The HisF subunit catalyzes the cyclization activity that produces IGP and AICAR from PRFAR using the ammonia provided by the HisH subunit.[HAMAP-Rule:MF_01013] Publication Abstract from PubMed Imidazole glycerol phosphate synthase (ImGPS) from Thermotoga maritima is a model enzyme for studying allostery. The ImGPS complex consists of the cyclase subunit HisF and the glutaminase subunit HisH whose activity is stimulated by substrate binding to HisF in a V-type manner. To investigate the significance of a putative closing hinge motion at the cyclase:glutaminase interface for HisH activity, we replaced residue W123 in HisH with the light-switchable unnatural amino acid phenylalanine-4'-azobenzene (AzoF). Crystal structure analysis employing angle, buried surface area, and distance measurements showed that incorporation of AzoF at this position causes a closing of the interface by approximately 18 +/- 3%. This slightly different interface configuration results in a much higher catalytic efficiency in unstimulated HisH due to an elevated turnover number. Moreover, the catalytic efficiency of HisH when stimulated by binding of a substrate to HisF was also significantly increased by AzoF incorporation. This was caused by a K-type stimulation that led to a decrease in the apparent dissociation constant for its substrate, glutamine. In addition, AzoF improved the apparent binding of a substrate analogue at the HisF active site. Remarkably, light-induced isomerization of AzoF considerably enhanced these effects. In conclusion, our findings confirm that signal transduction from HisF to HisH in ImGPS involves the closing of the cyclase:glutaminase subunit interface and that incorporation of AzoF at a hinge position reinforces this catalytically relevant conformational change. Significance of the Protein Interface Configuration for Allostery in Imidazole Glycerol Phosphate Synthase.,Kneuttinger AC, Rajendran C, Simeth NA, Bruckmann A, Konig B, Sterner R Biochemistry. 2020 Jul 13. doi: 10.1021/acs.biochem.0c00332. PMID:32633500 From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. See Also IGPS 3D structures

spinqualitylabelsall models 6ymu, resolution 2.11Å Show:Asymmetric Unit Biological Assembly Drag the structure with the mouse to rotate   Export Animated Image