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Crystal structure of Thermus thermophilus HB8 H-protein of the glycine cleavage system
Structural highlights
FunctionGCSH_THET8 The glycine cleavage system catalyzes the degradation of glycine. The H protein shuttles the methylamine group of glycine from the P protein to the T protein (By similarity).[HAMAP-Rule:MF_00272] Evolutionary Conservation Check, as determined by ConSurfDB. You may read the explanation of the method and the full data available from ConSurf. Publication Abstract from PubMedThe glycine-cleavage system is a multi-enzyme complex consisting of four different components (the P-, H-, T- and L-proteins). Recombinant H-protein corresponding to that from Thermus thermophilus HB8 has been overexpressed, purified and crystallized. Synchrotron radiation from BL44B2 at SPring-8 was used to collect a native data set to 2.5 A resolution. The crystals belonged to the hexagonal space group P6(5) and contained three molecules per asymmetric unit, with a solvent content of 39%. Because of the large number of molecules within a closely packed unit cell, this structure was solved by six-dimensional molecular replacement with the program EPMR using the pea H-protein structure as a search model and was refined to an R factor of 0.189 and a free R factor of 0.256. Comparison with the pea H-protein reveals two highly conserved regions surrounding the lipoyl-lysine arm. Both of these regions are negatively charged and each has additional properties that are conserved in H-proteins from many species, suggesting that these regions are involved in intermolecular interactions. One region has previously been proposed to constitute an interaction surface with T-protein, while the other may be involved in an interaction with P-protein. Meanwhile, the lipoyl-lysine arm of the T. thermophilus H-protein was found to be more flexible than that of the pea H-protein, supporting the hypothesis that H-protein does not form a stable complex with L-protein during the reaction. Structure of Thermus thermophilus HB8 H-protein of the glycine-cleavage system, resolved by a six-dimensional molecular-replacement method.,Nakai T, Ishijima J, Masui R, Kuramitsu S, Kamiya N Acta Crystallogr D Biol Crystallogr. 2003 Sep;59(Pt 9):1610-8. Epub 2003, Aug 19. PMID:12925792[1] From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine. References | ||||||||||||||||||
