{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,10,4]],"date-time":"2026-10-04T17:47:15Z","timestamp":1791136035898,"version":"4.1.0"},"reference-count":0,"publisher":"National Academy of Sciences","issue":"5","content-domain":{"domain":["www.pnas.org"],"crossmark-restriction":true},"short-container-title":["Proc. Natl. Acad. Sci. U.S.A."],"published-print":{"date-parts":[[1994,3]]},"abstract":"<jats:p>Ten mutants of bacteriorhodopsin, each containing\na single cysteine residue regularly spaced along helix D and facing the lipid\nbilayer, were derivatized with a nitroxide spin label. Collision rates of the\nnitroxide with apolar oxygen increased with distance from the membrane\/solution\ninterface. Collision rates with polar metal ion complexes decreased over the\nsame distance. Although the collision rates depend on steric constraints imposed\nby the local protein structure and on the depth in the membrane, the ratio of\nthe collision rate of oxygen to those of a polar metal ion complex is\nindependent of structural features of the protein. The logarithm of the ratio is\na linear function of depth within the membrane. Calibration of this ratio\nparameter with spin-labeled phospholipids allows localization of the individual\nnitroxides, and hence the bacteriorhodopsin molecule, relative to the plane of\nthe phosphate groups of the bilayer. The spacing between residues is consistent\nwith the pitch of an alpha-helix. These results provide a general strategy for\ndetermining the immersion depth of nitroxides in bilayers.<\/jats:p>","DOI":"10.1073\/pnas.91.5.1667","type":"journal-article","created":{"date-parts":[[2006,5,31]],"date-time":"2006-05-31T09:05:56Z","timestamp":1149066356000},"page":"1667-1671","update-policy":"https:\/\/doi.org\/10.1073\/pnas.cm10313","source":"Crossref","is-referenced-by-count":359,"title":["A collision gradient method to determine the immersiondepth of nitroxides in lipid bilayers: application to spin-labeled mutants ofbacteriorhodopsin."],"prefix":"10.1073","volume":"91","author":[{"given":"C","family":"Altenbach","sequence":"first","affiliation":[{"name":"Jules Stein Eye Institute, Los Angeles,\rCA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"D A","family":"Greenhalgh","sequence":"additional","affiliation":[{"name":"Jules Stein Eye Institute, Los Angeles,\rCA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"H G","family":"Khorana","sequence":"additional","affiliation":[{"name":"Jules Stein Eye Institute, Los Angeles,\rCA."}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"W L","family":"Hubbell","sequence":"additional","affiliation":[{"name":"Jules Stein Eye Institute, Los Angeles,\rCA."}],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"341","published-online":{"date-parts":[[1994,3]]},"container-title":["Proceedings of the National Academy of Sciences"],"original-title":[],"language":"en","link":[{"URL":"https:\/\/pnas.org\/doi\/pdf\/10.1073\/pnas.91.5.1667","content-type":"unspecified","content-version":"vor","intended-application":"similarity-checking"}],"deposited":{"date-parts":[[2022,4,13]],"date-time":"2022-04-13T14:04:08Z","timestamp":1649858648000},"score":1,"resource":{"primary":{"URL":"https:\/\/pnas.org\/doi\/full\/10.1073\/pnas.91.5.1667"}},"subtitle":[],"short-title":[],"issued":{"date-parts":[[1994,3]]},"references-count":0,"journal-issue":{"issue":"5","published-print":{"date-parts":[[1994,3]]}},"alternative-id":["10.1073\/pnas.91.5.1667"],"URL":"https:\/\/doi.org\/10.1073\/pnas.91.5.1667","relation":{},"ISSN":["0027-8424","1091-6490"],"issn-type":[{"value":"0027-8424","type":"print"},{"value":"1091-6490","type":"electronic"}],"subject":[],"published":{"date-parts":[[1994,3]]},"assertion":[{"value":"1994-03-01","order":2,"name":"published","label":"Published","group":{"name":"publication_history","label":"Publication History"}}]}}