2bkm: Difference between revisions

A novel truncated hemoglobin has been identified in the thermophilic, bacterium Geobacillus stearothermophilus (Gs-trHb). The protein has been, expressed in Escherichia coli, the 3D crystal structure (at 1.5 Angstroms, resolution) and the ligand binding properties have been determined. The, distal heme pocket displays an array of hydrogen bonding donors to the, iron-bound ligands, including Tyr-B10 on one side of the heme pocket and, Trp-G8 indole nitrogen on the opposite side. At variance with the highly, similar Bacillus subtilis hemoglobin, Gs-trHb is dimeric both in the, crystal and in solution and displays several unique structural properties., In the crystal cell, the iron-bound ligand is not homogeneously, distributed within each distal site such that oxygen and an acetate anion, can be resolved with relative occupancies of 50% each. Accordingly, equilibrium titrations of the oxygenated derivative in solution with, acetate anion yield a partially saturated ferric acetate adduct. Moreover, the asymmetric unit contains two subunits and sedimentation velocity, ultracentrifugation data confirm that the protein is dimeric.

2BKM is a [http://en.wikipedia.org/wiki/Single_protein Single protein] structure of sequence from [http://en.wikipedia.org/wiki/Geobacillus_stearothermophilus Geobacillus stearothermophilus] with ACT, OXY and HEM as [http://en.wikipedia.org/wiki/ligands ligands]. Structure known Active Site: AC1. Full crystallographic information is available from [http://ispc.weizmann.ac.il/oca-bin/ocashort?id=2BKM OCA].  

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