ABCMdb

PMID: 25886173

Golin J, Ambudkar SV
The multidrug transporter Pdr5 on the 25th anniversary of its discovery: an important model for the study of asymmetric ABC transporters.
Biochem J. 2015 May 1;467(3):353-63. doi: 10.1042/BJ20150042., [PubMed]

Sentences

No. Mutations Sentence Comment

160 ABCB3 p.Val656Leu Perhaps the most important mutant in the collection was a V656L substitution that lies in cis orientation in ICL2 with respect to the Q-loop [19,20]. Login to comment 161 ABCB3 p.Val656Ala Our group also constructed and tested a V656A mutant and showed that it was clearly signal-deficient. Login to comment 163 ABCB3 p.Val656Ala The V656A mutant had a phenotype that was nearly identical with that of S558Y, including an ATPase that was reduced relative to WT, but markedly resistant to allosteric inhibition by clotrimazole (5-fold as resistant as the WT). Login to comment 165 ABCB3 p.Val656Leu Further evidence for the cis interface came from our observation that V656L was also a strong suppressor of the cis Q-loop drug-hypersensitive mutation E244G. Login to comment 200 ABCB3 p.Val656Leu ABCB3 p.Val656Ala Therefore these mutants altered the stimulation signal, much like S558Y, V656L and V656A altered the trans-inhibition of Pdr5 ATPase by clotrimazole [18-20]. Login to comment 208 ABCB3 p.Val656Leu ABCB3 p.Val656Leu Three, V656L, P596L and A670S, were in regions making up the predicted Pdr5 signal interface (V656L and P596L were also represented in our suppressor mutant hunt). Login to comment 209 ABCB3 p.Val656Leu Clues about how these alleles might manipulate the interface to create greater drug resistance came from our in-depth study of V656L [20]. Login to comment 213 ABCB3 p.Val656Leu Furthermore, whereas the V656L suppression of E244G restored drug-resistance to WT levels, the reduced level of ATPase activity seen in the E244G mutant remained. Login to comment 214 ABCB3 p.Val656Leu ABCB3 p.Val656Leu ABCB3 p.Val656Leu ABCB3 p.Val656Leu Taken together, the behaviour of V656L and the E244G/V656L double mutant suggested that the V656L substitution increased resistance in one of two ways. It is plausible that the V656L mutant increases the efficiency with which the energy from ATP binding and/or hydrolysis is used for transport. Login to comment 245 ABCB3 p.Val656Ala The mutant phenotype was therefore much like those of other signalling mutants, such as S558Y and V656A. Login to comment 282 ABCC7 p.His1348Ala Recently, however, Csanady et al. [63] studied the properties of the degenerate site C-loop substitution H1348A. Login to comment 287 ABCB1 p.Glu1013Ala Gupta et al. [24] demonstrated further that replacement of multiple (Walker A, Walker B, and C-loop) deviant motifs with canonical ones in Pdr5 caused a significant loss, but not a complete elimination, of both ATPase and transport functions, rather reminiscent of the E1013A and D1042E phenotypes seen by Furman et al. [23]. Login to comment