ABCMdb

ABCB2 p.Ala160Cys

Predicted by SNAP2:	C: N (87%), D: N (57%), E: N (61%), F: N (97%), G: N (87%), H: N (87%), I: N (87%), K: N (78%), L: N (97%), M: N (87%), N: N (82%), P: N (61%), Q: N (82%), R: N (78%), S: N (93%), T: N (97%), V: N (93%), W: N (61%), Y: N (93%),
Predicted by PROVEAN:	C: N, D: N, E: N, F: N, G: N, H: N, I: N, K: N, L: N, M: N, N: N, P: N, Q: N, R: N, S: N, T: N, V: N, W: N, Y: N,

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[hide] Biochemical characterization of domains in the mem... Biochemistry. 2005 Feb 22;44(7):2661-70. Kaur P, Rao DK, Gandlur SM
Biochemical characterization of domains in the membrane subunit DrrB that interact with the ABC subunit DrrA: identification of a conserved motif.
Biochemistry. 2005 Feb 22;44(7):2661-70., 2005-02-22 [PMID:15709779]

Abstract [show]
DrrA and DrrB proteins confer resistance to the commonly used anticancer agents daunorubicin and doxorubicin in the producer organism Streptomyces peucetius. The drrAB locus has previously been cloned in Escherichia coli, and the proteins have been found to be functional in this host. DrrA, a soluble protein, belongs to the ABC family of proteins. It forms a complex with the integral membrane protein DrrB. Previous studies suggest that the function and stability of DrrA and DrrB are biochemically coupled. Thus, DrrA binds ATP only when it is in a complex with DrrB in the membrane. Further, DrrB is completely degraded if DrrA is absent. In the present study, we have characterized domains in DrrB that may be directly involved in interaction with DrrA. Several single-cysteine substitutions in DrrB were made. Interaction between DrrA and DrrB was studied by using a cysteine to amine chemical cross-linker that specifically cross-links a free sulfhydryl group in one protein (DrrB) to an amine in another (DrrA). We show here that DrrA cross-links with both the N- and the C-terminal ends of the DrrB protein, implying that they may be involved in interaction. Furthermore, this study identifies a motif within the N-terminal cytoplasmic tail of DrrB, which is similar to a motif recently shown by crystal structure analysis in BtuC and previously shown by sequence analysis to be also present in exporters, including MDR1. We propose that the motif present in DrrB and other exporters is actually a modified version of the EAA motif, which was originally believed to be present only in the importers of the ABC family. The present work is the first report where domains of interaction in the membrane component of an ABC drug exporter have been biochemically characterized.

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77 The mutants were named S4C, S15C, S23C, S35C, A44C, C260S up: 5'-GGCCTGGTCCTGTCCGTGTCGGCAGGG-3' C260S dn: 5'-CCCTGCCGACACGGACAGGACCAGGCC-3' S23C up: 5'- CGGACGGTGCTGTGCGCGGGTGAACGG-3' S23C dn: 5'- CCGTTCACCCGCGCACAGCACCGTCCG-3' V53C, T70C, S80C, V92C, S107C, V116C, A129C, T149C, A160C, V173C, S213C, S236C, T249C, A270C, and A282C, respectively. Login to comment
193 The location of the cross-linked species is marked as A+B. (A) S23C (positive control), A129C, T149C, A160C. Login to comment
196 Table 1: Doxorubicin Resistance of E. coli N43 Cells Expressing Wild Type DrrA with DrrB Containing Different Cysteine Substitutionsa amt of dox, µg/mLdomain of DrrB location of cysteine 0 4 6 8 (wild type) C260 +++ +++ +++ ++ N-terminus S15C +++ +++ +++ ++ N-terminus S23C +++ +++ +++ ++ N-terminus S35C +++ +++ ++ ++ N-terminus A44C +++ +++ ++ + TM 1 V53C +++ ++ ++ - TM 1 T70C +++ + + + P 1 S80C +++ ++ + - TM 2 V92C +++ ( - - TM 2 S107C +++ +++ ++ ++ C 1 V116C +++ +++ +++ ++ TM 3 A129C +++ ++ + - TM 4 T149C +++ ++ ++ + C 2 A160C +++ +++ ++ + TM 5 V173C +++ +++ ++ + TM 6 S213C +++ +++ ++ + C 3 S236C +++ ++ + - TM 7 S249C +++ + + - TM 8 A270C +++ +++ ++ ++ C-terminus A282C +++ +++ ++ ++ cysteine-less DrrB C260S +++ +++ +++ +++ vector only pSU2718 ++++ ( - - a Legend: +++, very good growth; ++, good growth; +, some growth; -, no growth. Login to comment