Detailed views of the area around NAD+ of Ia mutants, E378S, E380A, and E380S. (A) Comparison of WT vs. E378S mutant; wild type of Ia is in yellow and E378S mutant is in green. (B) Comparison of WT vs. two E380 mutants. Wild type is in yellow, E380A mutant is in purple, and E380S mutant is in blue. All actins are in green. Y251, R295, R296, Q300, N335, R352, Y375, E378, and E380 are labeled in Ia.