Figure 1 | Scientific Reports

Figure 1

From: K336I mutant actin alters the structure of neighbouring protomers in filaments and reduces affinity for actin-binding proteins

Figure 1

Properties of purified K336I monomeric actin. (A) The release rate of ε-ATP from K336I and WT actin monomers was monitored by measuring the decrease in fluorescence intensity after the addition of regular ATP (1 mM) to 20 µM K336I or WT G-actin that had been incubated with ε-ATP. The dissociation rates of ε-ATP from K336I mutant actin and WT actin were 0.009 ± 0.001 s−1 and 0.025 ± 0.005 s−1, respectively (mean ± SE, N = 3). There is a statistically significant difference between K336I and WT actin (t-test, p < 0.01). (B) K336I and WT actin (4 µM) were treated with 0.5 µg/ml subtilisin for the indicated time, and analysed by SDS-PAGE. Arrows indicate intact actin bands (42 kDa) and arrowheads indicate digested actin bands (36 kDa). MW, molecular weight markers. Full-length gel image is shown in Supplementary Fig. S3. (C) Quantitation of intact actin bands from Coomassie-stained gels, including the one shown in (B). After 3 minutes of subtilisin digestion, 52.1 ± 4.3% of K336I G-actin was intact, vs. 29.6 ± 6.4% of WT G-actin (mean ± SE, N = 3).

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