Fig. 2.

S. cerevisiae Oxa1 complements a lack of YidC2 in S. mutans. (A) ATPase-specific activities of membrane fractions prepared from parent, mutant, and complemented mutant strains were calculated and expressed as nanomoles of phosphate released per minute per milligram of total protein. Statistical significance relative to the parent is indicated by an asterisk, with P < 0.001 using a 2-tailed t test (alpha = 0.05). (B) Genetic competence was assessed by natural transformation using plasmid pDC123 (Cm^r). The transformation efficiency is indicated as the percentage of transformants of the mutant or complemented mutant strains compared to the S. mutans parent strain. Statistical significance relative to the ΔyidC2 and ΔyidC2 + Cox18 strains was P < 0.001(*) and P < 0.05(^†) using a 2-tailed t test (alpha = 0.05).