. Author manuscript; available in PMC: 2009 Sep 1.

Published in final edited form as: Biochim Biophys Acta. 2008 May 10;1784(9):1222–1225. doi: 10.1016/j.bbapap.2008.04.027

Table 2.

Ratio of k_cat/K_M for aminoacylation of wild-type and mutant tRNA^Pro by wild-type and mutant ProRS^a

	G72A	A73G	2AP72	7G72	7A73
ProRS (WT)	170	175	30	52	23
R144K (−480)	2.6	1.0	2.5	2.1	7.4
R144L (−870)	0.42	0.91	0.43	0.06	18
V143C (−3)	230	310	ND	ND	ND
R146C (−79)	>10⁶	>10⁶	ND	ND	ND

2AP is 2′-deoxy-2-aminopurine, 7G is 2′-deoxy-7-deaza-G, and 7A is 2′–deoxy-7-deaza A. The 2′–hydroxyl group was previously shown to be dispensable at positions 72 [12] and 73 [5]. The ratios were obtained as follows: (k_cat/K_M)_{wild-type tRNA}/(k_cat/K_M)_{mutant tRNA}. ND stands for not determined. The numbers in parenthesis (left column) indicate the fold-decrease in the wild-type (WT) tRNA^Pro aminoacylation efficiency of the indicated mutant ProRS, relative to WT ProRS (in the case of R144K and R144L) or relative to C443G ProRS (in the case of V143C and R146C, see Materials and Methods). All assays were performed at least twice with a difference of < 2-fold between trials.