title: Effect of succinylation on images of negatively stained arrays of mitochondrial outer membrane channels.
abstract: The voltage-dependent anion-selective channels of the outer membrane of Neurospora mitochondria occur in two-dimensional crystalline arrays. Electron microscopic images of negatively stained arrays have been compared for normal membranes and membranes pretreated with succinic anhydride, which changes the functional characteristics of the channel. Succinic anhydride does not alter the lattice parameters or the long-range order in the arrays. Also, it has no significant effect on correlation averages of channel arrays embedded in uranyl acetate. Thus, functional changes induced in the channel by succinic anhydride are probably not due to large-scale conformational changes. The distribution of the anionic stain phosphotungstate on the mitochondrial channel arrays is significantly altered by succinic anhydride pretreatment. There are loci on the channels of reduced phosphotungstate accumulation following succinylation. Since phosphotungstate selectively stains positively charged amino acids, it is proposed that these loci may represent clusters of functionally important, exposed basic amino acids.
mesh_terms: D000838:Anions / Q000378:metabolism*; D003460:Crystallization; D007473:Ion Channels / Q000032:analysis* / Q000187:drug effects; D008928:Mitochondria / Q000032:analysis* / Q000187:drug effects / Q000648:ultrastructure; D009491:Neurospora / Q000032:analysis*; D009492:Neurospora crassa / Q000032:analysis*; D010772:Phosphotungstic Acid; D013194:Staining and Labeling; D013386:Succinates / Q000494:pharmacology*; D013387:Succinic Anhydrides / Q000494:pharmacology*
chemical_list: D000838:Anions; D007473:Ion Channels; D013386:Succinates; D013387:Succinic Anhydrides; D010772:Phosphotungstic Acid; C031801:succinic anhydride