ABCG2 p.His583Ala
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PMID: 20705604
[PubMed]
Desuzinges-Mandon E et al: "ABCG2 transports and transfers heme to albumin through its large extracellular loop."
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6
Single-point mutations H583A and C603A inside ECL3 prevent the binding of hemin but hardly affect that of iron-free PPIX.
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ABCG2 p.His583Ala 20705604:6:23
status: VERIFIED220 Single-point Mutations H583A and C603A of ECL3 Alter Hemin Binding-We noticed that ECL3 displays a significant sequence similarity with the heme-binding domain of cytochrome b5, with 14.3% identity and 15.6% similarity, as shown in Fig. 6A.
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ABCG2 p.His583Ala 20705604:220:23
status: VERIFIED224 As shown, the most striking differences were observed for hemin binding because the H583A and C603A mutations lowered the binding affinity 5-6-fold.
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ABCG2 p.His583Ala 20705604:224:84
status: VERIFIED245 B, dissociation constants for hemin and PPIX binding to H583A, C603A, and Y605A mutant ECL3.
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ABCG2 p.His583Ala 20705604:245:56
status: VERIFIED278 Heme and hemin appear to be the preferred ligands, because (i) they display the highest binding affinities for both the isolated ECL3 domain (0.5-1 M) and the full-length ABCG2 transporter (0.2 M); (ii) the H583A and C603A single-point mutations alter more markedly the binding of hemin than that of metal-free corresponding PPIX; and (iii) pheophorbide a, which is transported by ABCG2 (26), displays a low binding affinity for ECL3 (3 M), which is even lower for the full protein (Ͼ8 M) when saturated with MTX or doxorubicin, suggesting that pheophorbide a will not bind to ECL3 under physiological conditions.
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ABCG2 p.His583Ala 20705604:278:223
status: VERIFIED