Role of a mitochondrial gene in the conformation and optical properties of mitochondrial cytochromes inNeurospora crassa

✍ Scribed by R. T. Eakin

• Publisher: Springer
• Year: 1974
• Tongue: English
• Weight: 749 KB
• Volume: 12
• Category: Article
• ISSN: 0006-2928
• DOI: 10.1007/bf00487525

✦ Synopsis

The mitochondrial cytoehrome spectrum of the poky strain of Neurospora crassa and its variation during the life cycle have been analyzed. Two factors are taken into account in addition to those usually considered," absorption in the near-ultraviolet Soret region and the physical nature of the electronic transitions which give rise to the absorption bands. From this extended analysis, a hypothesis based on the chemical nature of the axial environment of the heme groups has been constructed to account for spectroscopic observations. A model has been developed that provides a biochemical mechanism by which a genetic defect in mitochondrial DNA can lead to structural defects in the axial environment of the heroes and thus to an altered cytochrome spectrum. Previously reported absences or deficiencies of cytochromes based on visible absorption spectroscopy may in some cases indicate the absence or deficiency of only the particular polypeptide subunits of a complex which are synthesized within the mitochondria. This interpretation is consistent with the various manifestations of the poky phenotype which have been observed.