Send to

Choose Destination
J Mol Biol. 1991 Apr 5;218(3):499-503.

Proline kinks in transmembrane alpha-helices.

Author information

Department of Molecular Biology, Karolinska Institute Center for Biotechnology, Huddinge, Sweden.


Integral membrane proteins often contain proline residues in their presumably alpha-helical transmembrane segments. This is in marked contrast to globular proteins, where proline is rarely found inside alpha-helices. Proline residues cause kinks in helices, and, in addition to leaving the i-4 backbone carbonyl without its normal hydrogen bond donor, also sterically prevent the (i-3)-carbonyl-(i + l)-amide backbone hydrogen bond from forming. Here, some structural aspects of proline kinks in transmembrane helices are discussed on the basis of an analysis of Pro-kinked helices in the photosynthetic reaction center and bacteriorhodopsin, as well as results from an analysis of Pro-containing transmembrane segments identified in the NBRF Protein Sequence Databank.

[Indexed for MEDLINE]

Supplemental Content

Full text links

Icon for Elsevier Science
Loading ...
Support Center