1LR6

Crystal structure of V45Y mutant of cytochrome b5

Summary for 1LR6

• Entry DOI: 10.2210/pdb1lr6/pdb
• Related: 1EHB 1ES1 1LQX
• Descriptor: cytochrome b5, PROTOPORPHYRIN IX CONTAINING FE (3 entities in total)
• Functional Keywords: cytochrome b5, trypsin-solubilized fragment, mutant v45y, electron transport
• Biological source: Bos taurus (cattle)
• Cellular location: Endoplasmic reticulum membrane; Single-pass membrane protein; Cytoplasmic side: P00171
• Total number of polymer chains: 1
• Total formula weight: 10155.91

Authors

Gan, J.-H.,Wu, J.,Wang, Z.-Q.,Wang, Y.-H.,Huang, Z.-X.,Xia, Z.-X. (deposition date: 2002-05-15, release date: 2002-09-04, Last modification date: 2023-10-25)

Primary citation

Gan, J.H.,Wu, J.,Wang, Z.Q.,Wang, Y.H.,Huang, Z.X.,Xia, Z.X.
Structures of V45E and V45Y mutants and structure comparison of a variety of cytochrome b5 mutants.
Acta Crystallogr.,Sect.D, 58:1298-1306, 2002

PubMed Abstract: Val45 is a highly conserved residue and a component of the heme-pocket wall of cytochrome b(5). The crystal structures of cytochrome b(5) mutants V45E and V45Y have been determined at high resolution. Their overall structures were very similar to that of the wild-type protein. However, Val45 of the wild-type protein points towards the heme, but the large side chains of both Glu45 and Tyr45 of the mutants point towards the solvent. A channel is thus opened and the hydrophobicity of the heme pocket is decreased. The rotation of the porphyrin ring and the conformational change of the axial ligand His39 in the V45Y mutant indicate that the microenvironment of the heme is disturbed because of the mutation. The binding constants and the electron-transfer rates between cytochrome b(5) and cytochrome c decrease owing to the mutation, which can be accounted for by molecular modeling: the inter-iron distances increase in order to eliminate the unreasonably close contacts resulting from the large volumes of the mutated side chains. The influence of the mutations on the redox potentials and protein stability is also discussed. The structures of seven mutants of cytochrome b(5) are compared with each other and the effects of these mutations on the protein properties and functions are summarized.

PubMed: 12136141
DOI: 10.1107/S0907444902010016

Experimental method

X-RAY DIFFRACTION (1.9 Å)