A model for the molecular organization of cytochrome beta-561 in chromaffin granule membranes.
The CD spectrum of reduced cytochrome (cyt.) beta-561 in chromaffin granule membranes resembles that of mitochondrial cyt. beta 1 and indicates possible heme-heme interaction in the protein. Based on spectroscopic data and analysis of the amino acid sequence, a model of cyt. beta-561 is suggested, in which the protein carries two transmembrane-localized hemes, each coordinated by two histidines. The model accounts for the presence of two different forms of cyt. beta-561 in chromaffin granule membranes and provides a mechanism of transmembrane electron transfer by this hemoprotein.
Dept of Biology, University of Bologna, Italy.
M
M
Degli Esposti
Kamensky YuA
A M
AM
Arutjunjan
A A
AA
Konstantinov
D000313:Adrenal Medulla / Q000201:enzymology*; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002837:Chromaffin Granules / Q000201:enzymology*; D002838:Chromaffin System / Q000201:enzymology*; D002942:Circular Dichroism; D003573:Cytochrome b Group / Q000302:isolation & purification*; D006418:Heme / Q000032:analysis; D007425:Intracellular Membranes / Q000201:enzymology; D008928:Mitochondria / Q000201:enzymology; D008958:Models, Molecular; D011487:Protein Conformation
D003573:Cytochrome b Group; C023646:cytochrome b561; D006418:Heme