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. Author manuscript; available in PMC: 2015 Mar 11.
Published in final edited form as: Biochemistry. 2011 Jan 11;50(5):854–863. doi: 10.1021/bi101005r

Figure 5.

Figure 5

Effects of helix 24 loop mutations on 30S assembly efficiency and methylation by KsgA. (A) The loop nucleotides (787-795) were replaced with GAAA, a member of the GNRA tetraloop family. G791 was mutated to each of A, C, and U. (B) and (C), respectively, show the sucrose gradient analysis for the 790-loop− mutant and the G791U mutant, which is representative of all three single G791 mutations. For G791 mutants, material corresponding to the 30S peak (peak 4 in G791U profile) was used for KsgA time course activity assays, while sucrose gradient fractions of earlier peaks (peaks 1, 2, and 3) were used in a 2-hr end point methylation assay. Fractions pooled for each peak are indicated by arrows matching in color to the peak number. (D) Time course activity assays for 30STag,UM subunits (red) and the three mutant subunits, 30STag,UM[G791A] (green), 30STag,UM[G791C] (blue), and 30STag,UM[G791U] (purple). (E) 2-hr end point methylation assay of sucrose gradient fractions of 30STag,UM (red), 30STag,UM[G791A] (green), 30STag,UM[G791C] (blue), and 30STag,UM[G791U] (purple).