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. 2021 Apr 30;22(9):4806. doi: 10.3390/ijms22094806

Table 4.

The human ABCG2 and fungal Cdr1 multidrug exporters share conserved motifs.

Location Conserved Motif Functional Role Human ABCG2 Candida albicans Cdr1
First Half Second Half
NBD Walker A ATP hydrolysis (phosphate binding) * G79–S88 G187–T195 G895–T903
Q-loop TMD–NBD communication Q126 E238 ** Q942
Hot spot Triple helical bundle L134–A149 L246–P261 S950–S965
Signature NBD dimerization and phosphate binding V186–R193 V303–R310 V996–R1008
Pro loop NBD dimerization P204 ? P1019
Walker B ATP hydrolysis I206–E211 I323–N238 L1021–E1027
D-loop NBD dimerization L216–D217 L333–D334 L1032–D1033
H-loop ATP hydrolysis H243 Y361 ** H1059
Elbow helix Conserved R Salt bridge, THB R383 R503 R1185
ECL1 Conserved R Salt bridge R426 R456 ?
TMH2 Conserved F Clamping F439 F559 F1239
ICL1 Conserved E (1) Salt bridge and intracellular gating E451 E570 D1255
Conserved E (2) Salt bridge E458 E576 E1261
Conserved Y Salt bridge, THB Y464 Y584 Y1257
TMH3 Conserved D/E Intracellular gating D477 E597 E1280
Valve Conserved hydrophobic Valve G553–L555 G672–V674 G1362–L1364
Re-entry helix Conserved P Kinked helix P574 P692 P1382
Conserved E Salt bridge E585 E704 ?
ECL3 Conserved C (1) Intra/intermolecular disulfide bond C592 C712 C1418
conserved C (2) Intra/intermolecular disulfide bond C603 ? C1441
conserved C (3) Intra/intermolecular disulfide bond C608 C732 C1444

* Some PDRs may consume GTP as well [186,331]. ** Substitution with another residue.