Выражение встречается в следующем контексте:
analysis of TMC207 mutants of M. tuberculosis and M. smegmatis showed that there were no mutations in the DNA gyrase regions gyrA и gyrB, sequences in which quinolone resistance typically develops. The genomes of the resistant M. tuberculosis strain BK12 and the genome of the parental M. smegmatis strain were sequenced to near-completion... The 2 point mutations identified, Asp32Val for M. smegmatis and Ala63Pro for M. tuberculosis are both in the membrane-spanning domain region of the protein.

С первым предложением все более-менее понятно. Но как перевести остальные??
Заранее спасибо