1qpu
From Proteopedia
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SOLUTION STRUCTURE OF OXIDIZED ESCHERICHIA COLI CYTOCHROME B562
Overview
The solution structure of the oxidized, paramagnetic form of cytochrome, b562 from Escherichia coli (106 amino acids) is here reported as obtained, from 1653 meaningful NOEs (from a total of 2051 unique NOEs), 33, (3)JHNHalpha values, and 339 pseudocontact shifts. The structure displays, the typical four-helix bundle motif, and a disordered loop between helices, alpha2 and alpha3, as found in the solid state. The solution structure has, a conformation intermediate between the two independent solid-state, molecules, although different orientations are observed for a few, residues. The magnetic susceptibility tensor is similar to that of, cytochrome c, which has the same ligands, although the anisotropy is, somewhat smaller. This difference in the electronic structure is, consistent with the thermal accessibility in cytochrome b562 of states, with S > 1/2. The structure is also compared with the solution structure, of the apoprotein, and some information on the role of the cofactor on the, protein folding and mobility is obtained. Helix alpha4 seems to be the, most sensitive to the chemical environment in terms of structure and, mobility. The pKa values affecting the hyperfine-shifted signals are also, discussed. Quite intriguing is the comparison of the structure of, cytochrome b562 with the available structures of cytochromes c' which, display a similar folding motif and similar pKa values but very little, sequence similarity.
About this Structure
1QPU is a Single protein structure of sequence from Escherichia coli with HEM as ligand. Full crystallographic information is available from OCA.
Reference
The solution structure of oxidized Escherichia coli cytochrome b562., Arnesano F, Banci L, Bertini I, Faraone-Mennella J, Rosato A, Barker PD, Fersht AR, Biochemistry. 1999 Jul 6;38(27):8657-70. PMID:10393541
Page seeded by OCA on Wed Nov 21 00:52:35 2007
