How hydrophobic is alanine?
2003 (English)In: Journal of Biological Chemistry, ISSN 0021-9258, E-ISSN 1083-351X, Vol. 278, no 32, 29389-29393 p.Article in journal (Refereed) Published
By a number of measures, alanine is poised at the threshold between those amino acids that promote the membrane integration of transmembrane alpha-helices and those that do not. We have measured the preference of alanine to partition into the lipid-water interface region over the central acyl chain region of the endoplasmic reticulum (ER) membrane both by its ability to promote the formation of so-called helical hairpins, i.e. a pair of transmembrane helices separated by a tight turn, and by mapping the position relative to the membrane of the lumenal end of a transmembrane alpha-helix that ends with a block of 10 alanines. Both measures show that Ala has a weak but distinct preference for the interface region, which is in agreement with recent biophysical measurements on pentaeptide partitioning in simple water-lipid or water-octanol systems (Jayasinghe, S., Hristova, K., and White, S. H. ( 2001) J. Mol. Biol. 312, 927 - 934). Considering the complexity of the translocon-mediated insertion of membrane proteins into the ER, the agreement between the biochemical and biophysical measurements is striking and suggests that protein-lipid interactions are already important during the very early steps of membrane protein assembly in the ER.
Place, publisher, year, edition, pages
2003. Vol. 278, no 32, 29389-29393 p.
Biochemistry and Molecular Biology
IdentifiersURN: urn:nbn:se:su:diva-19158DOI: 10.1074/jbc.M212310200ISI: 000184507000002PubMedID: 12761228OAI: oai:DiVA.org:su-19158DiVA: diva2:185681