Characterization of the 9.5-kDa ubiquinone-binding protein of NADH:Ubiquinone oxidoreductase (complex I) from Neurospora crassa

• Type: Article in International Scientific Journal
• Date: 1992

Authors

heinrich, h (Author) Other; azevedo, je (Author) ICBAS; werner, s (Author) Other

Journal

Title: Biochemistry

Pages: 11420-11424

ISSN: 0006-2960

Publisher: American Chemical Society

Indexing

ISI Web of Knowledge

Scopus - 13 Citations

Scientific classification

FOS: Natural sciences

Other information

Authenticus ID: P-007-5HN

Abstract (EN): A small polypeptide subunit of the NADH:ubiquinone reductase (complex I) from Neurospora crassa has been identified by photoaffinity labeling to participate in the binding of ubiquinone [Heinrich, H., & Werner, S. (1992) Biochemistry (preceding paper in this issue)]. This polypeptide is further characterized by its primary structure and by an assessment of its localization within complex I. A λgt11 cDNA expression library was screened using a specific antibody directed against this individual subunit of complex I. Two groups of clones, coding for polypeptide subunits of the appropriate apparent molecular weight, were isolated. One group was shown to contain the relevant recombinants. The derived amino acid sequence for the 9.5-kDa ubiquinone-binding polypeptide shows a similarity with a putative ubiquinol-binding subunit (also a 9.5-kDa polypeptide) from complex III of bovine heart [Usui, S., Yu, L., & Tu, C.-A. (1990) Biochemistry 29, 4618-4626]. The polypeptide has a hydrophobic stretch of a sufficient length to span the membrane. It resists against extraction with NaBr or Na2CO3, and therefore probably is buried in the so-called hydrophobic membrane portion of complex I. This nuclearly-encoded subunit lacks a typical cleavable presequence and is imported into isolated mitochondria by a membrane potential-dependent process. © 1992 American Chemical Society.

Language: English

Type (Professor's evaluation): Scientific