Functional consequences of the excision of an omega loop, residues 40-55, from mitochondrial cytochrome c.

A novel technique for protein semisynthesis, enzymic activation, has been used to create a mitochondrial cytochrome c analogue in which the conventional bottom loop has been deleted. The resulting structure resembles that of cytochrome c555 from a primitive photosynthetic sulfur bacteria. Comparisons of this analogue with natural cytochromes show which of the functional differences between cytochromes c and c555 may be related directly to the incorporation of the loop. The structure is an example of an omega loop, recently defined as a discrete category of protein secondary structure. The analogue maintains the overall structure of the parent protein, but a significant change in redox potential has been engineered. It provides support for the prediction that omega loops act as independent modules in folding, function, and evolution. The rapidity of the synthesis and the high yield of product show that this technique for protein engineering is both competitive with, and complementary to, genetic methods.

• Publication year

  1987

• Venue

  Journal of Biological Chemistry

• Publication date

  1987-12-15

• Fields of study

  Biology, Medicine, Chemistry

• Identifiers
  DOI 10.1016/s0021-9258(18)45449-xPMID 2824505
• External record

  Open on Semantic Scholar

• Source metadata

  Semantic Scholar, PubMed

• No claims are published for this paper.

• No concepts are published for this paper.

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