. "Protein with at least one transmembrane helical domain, a membrane-spanning domain with an hydrogen-bonded helical configuration, including alpha-, 3-10-, and pi-helices. The transmembrane alpha-helix is very common, while the 3-10-helix is found at the ends of alpha-helices and the pi-helix, is more rare." . . . "Transmembrane helix" . "Alpha-helical transmembrane" . "Pauling-Corey-Branson alpha helix" . .