Alternative divalent cations (Zn2+, Co2+, and Mn2+) are not mutagenic at conditions optimal for HIV-1 reverse transcriptase activity

Table 1 Synthesis rate on the RNA template for the PCR-based α-complementation fidelity assay at different cation concentrations

Cation	^a Optimal concentration	^b Maximal extension rate	^b Average extension rate
Cation	mM	nts/sec	nts/sec
Mg²⁺	2 (1.6)	7.4 ± 1.9	1.8 ± 0.5
Mn²⁺	0.4 (0.15)	1.2 ± 0.3	0.48 ± 0.09
Co²⁺	0.25 (0.07)	1.1 ± 0.1	0.23 ± 0.05
Zn²⁺	0.4 (0.15)	0.19 ± 0.10	0.03 ± 0.02

^aThe concentration of free cation is shown in parenthesis. Free cation concentration for Mg²⁺ was calculated as described in Materials and Methods using the dissociation constant for Mg²⁺ and ATP. Free concentrations for alternative cations (Mn²⁺, Co²⁺, and Zn²⁺) were approximately using the dissociation constant for Mg²⁺ and ATP.
^bValues are averages from 3 experiments ± standard deviation. Rates were calculated as described in Materials and Methods.

ISSN: 1471-2091