HIV-1 MA mutations analyzed for their effect on Gag membrane binding. At the top is indicated the linear organization of the Gag precursor Pr55Gag showing MA, CA, NC, and p6 domains. MA mutations were analyzed in the contexts of full-length Pr55Gag, a truncated Gag containing MA-CA (p41stop), and MA alone (MAstop). The locations of the five major α-helices in MA (H1 to H5) are indicated; the N terminus of MA and the sequences surrounding residues 20 and 97 are enlarged. The positions of the mutations are indicated. Dashes denote sequence identity with wild type (w.t.). The myristylation consensus sequence is underlined.