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. 2010 Aug 17;285(42):32105–32115. doi: 10.1074/jbc.M110.165084

FIGURE 1.

FIGURE 1.

Alignment of the a-subunit putative transmembrane helices 4 and 5 and a diagrammatic representation of all the mutants in the study. A, putative TMH4 and TMH5 are shown for the following organisms, with their accession numbers in parentheses. Alkaliphiles are shaded. They are the extreme alkaliphiles B. pseudofirmus OF4 (AAG48358), B. halodurans C-125 (NP_244625.1) and B. alcalophilus (P25965), the more moderately alkaliphilic B. clausii KSM-K16 (Q5WB72), B. selenitireducens MLS10 (CP001791), and thermoalkaliphile C. thermarum TA2.A1 (AAQ10084). The non-alkaliphilic Bacillus species are B. licheniformis (YP_093439), B. megaterium (AAA82520), B. subtilis 168 (NP_391568), and G. kaustophilus HTA42 (YP_149217); also included is the model Gram-negative E. coli K12 (YP_001732559). Residue numbers above the alignment are those for the B. pseudofirmus OF4 protein; the numbers in parentheses below the alignment refer to the E. coli protein. Gray shading highlights the Lys-180 and putatively interacting Gly-212 that are both found exclusively in alkaliphiles, although not in B. clausii or B. selenitireducens MLS10. Two additional deviations from the consensus sequence for non-alkaliphilic Bacillus species that are found in all of the alkaliphiles except for thermoalkaliphile C. thermarum TA2.A1 are boxed for alkaliphiles (Met-171 and Met-184) and underlined for the thermoalkaliphile. Some residues only found in most alkaliphiles but not all alkaliphiles are also boxed (Val-177, Ile-185, and Leu-205). B, a topological representation of the putative five-transmembrane helix structure of the B. pseudofirmus OF4 a-subunit with the location of the residues in TMH4 and -5 that were mutated as well as selected alkaliphile-specific residues of interest in other regions that are not conserved in the a-subunit from thermoalkaliphile C. thermarum; the replacements made in each location are indicated. Residues mutated to the residue found in C. thermarum at that position have a white background while other mutations have a black background.