ABCMdb

PMID: 23378596

Hunt JF, Wang C, Ford RC
Cystic fibrosis transmembrane conductance regulator (ABCC7) structure.
Cold Spring Harb Perspect Med. 2013 Feb 1;3(2):a009514. doi: 10.1101/cshperspect.a009514., [PubMed]

Sentences

No. Mutations Sentence Comment

118 ABCC7 p.Glu1371Gln One key observation supporting this model is that electrophysiological studies show that the E-to-Q mutation in NBD2 of CFTR (E1371Q) produces a very long-lived open state of the channel in the presence of ATP (Vergani et al. 2005; Gadsby et al. 2006; Hwang et al. 2009). Login to comment 163 ABCC7 p.Arg553Gln ABCC7 p.Gly550Glu ABCC7 p.Arg555Lys One such set, called the Teem set, comprised three point mutations (G550E/ R553Q/R555K) that previously were shown to promote improved biogenesis of F508del CFTR in tissue cultures cells, presumably by improving the stability of the protein (Teem et al. 1993; DeCarvalho et al. 2002). Login to comment 164 ABCC7 p.His667Arg ABCC7 p.Phe429Ser ABCC7 p.Phe409Leu ABCC7 p.Phe433Leu (This mutation set is found in combination with the F409L, F429S, F433L, and H667R mutations in PDB IDs 1XMJ and 2BBO.) Login to comment 165 ABCC7 p.His667Arg ABCC7 p.Phe429Ser ABCC7 p.Phe429Ser ABCC7 p.Phe494Asn ABCC7 p.Phe494Asn ABCC7 p.Gln637Arg ABCC7 p.Gln637Arg The other mutation sets that improved the yield of soluble hNBD1 involved substitution of surface-exposed residues in hNBD1 with more polar residues occurring at the same position in CFTR orthologs from other species (F429S/F494N/ Q637R found in PDB ID 2BBS, F494N/ Q637R found in PDB ID 2BBT, and F429S/ H667R found in PDB ID 1XMI). Login to comment 236 ABCC7 p.Arg553Gln ABCC7 p.His667Arg ABCC7 p.Gly550Glu ABCC7 p.Arg555Lys ABCC7 p.Phe429Ser ABCC7 p.Phe409Leu ABCC7 p.Phe433Leu Note that the structures shown here contain seven point mutations included in hNBD1 constructs because of their beneficial influence on yield during purification-F409L, F429S, F433L, G550E, R553Q, R555K, and H667R. Login to comment 255 ABCC7 p.Arg1070Trp A second-site R1070W mutation in the proximal region of the TMDs produces significant suppression of the defect (Thibodeau et al. 2010), presumably by increasing hydrophobic interactions with the altered conformation of residue V510 in F508del-NBD1. Login to comment 256 ABCC7 p.Val510Asp ABCC7 p.Arg1070Ala ABCC7 p.Arg1070Asp Moreover, restoration of the trafficking of F508del-NBD1 by the V510D suppressor mutation, which introduces a negative charge into a generally apolar region J.F. Hunt et al. 16 Cite this article as Cold Spring Harb Perspect Med 2012;3:a009514 www.perspectivesinmedicine.org by Cold Spring Harbor Laboratory Press at SEMMELWEIS UNIV OF MEDICINE on December 5, of the interdomain interface (Fig. 4C,D), is strongly attenuated by introducing the R1070A or R1070D mutations that remove a complementary positive charge from the proximal surface of the TMD (Loo et al. 2010). Login to comment 262 ABCC7 p.Ile539Thr In contrast, the third recent paper showed essentially wild-type levels of maturation and stability in F508del-CFTR containing second-site suppressor mutations exclusively in NBD1 (i.e., the I539T mutation plus four proline substitutions found in chicken CFTR, which is naturally more thermostable than human CFTR) (Aleksandrov et al. 2012). Login to comment 275 ABCC7 p.Arg553Gln ABCC7 p.Gly550Glu ABCC7 p.Arg555Lys ABCC7 p.Val510Asp ABCC7 p.Phe494Asn ABCC7 p.Gln637Arg A series of second-site mutations in NBD1 have parallel effects in rescuing the trafficking defect in CFTR in vivo (DeCarvalho et al. 2002; Pissarra et al. 2008; Aleksandrov et al. 2010) and inhibiting molten globule formation by isolated NBD1 in vitro (G550E/R553Q/R555K, F494N/Q637R, or V510D) (Protasevich et al. 2010; Wang et al. 2010). Login to comment 289 ABCC7 p.His1402Ala ABCC7 p.Tyr1307Asn ABCC7 p.Gln1411Asp ABCC7 p.Trp1310His ABCC7 p.Gln1280Glu Improvements in the yield of soluble protein were obtained by introducing the hydrolytically inactivating H1402A mutation in ATPase active site of hNBD2 plus a series of "solubilizing" mutations on its surface (Q1280E/ Y1307N/W1310H/Q1411D) (X Zhao, S Atwell, JF Hunt, et al., unpubl.). Login to comment 290 ABCC7 p.Glu1308Ala ABCC7 p.Gln1309Ala Two additional "surface entropy reduction" mutations (E1308A/ Q1309A) were introduced into the construct to promote crystallization. Login to comment 291 ABCC7 p.His1402Ala The H1402A mutation as well as at least some of the "solubilizing" mutations seem likely to stabilize the native conformation of the domain thermodynamically, as observed for the solubilizing surface mutations that improved the stability and yield J.F. Hunt et al. 18 Cite this article as Cold Spring Harb Perspect Med 2012;3:a009514 www.perspectivesinmedicine.org by Cold Spring Harbor Laboratory Press at SEMMELWEIS UNIV OF MEDICINE on December 5, of preparations of hNBD1 (as described above). Login to comment 293 ABCC7 p.His1402Ala Nonetheless, indirect evidence supports the hypothesis that the H1402A mutation stabilizes hNBD2. Login to comment 295 ABCC7 p.His1402Ala ABCC7 p.His1402Ala ABCC7 p.Glu1371Gln ABCC7 p.Glu1371Gln Electrophysiological studies of the H1402A and E1371Q mutations in intact human CFTR support these inferences concerning catalytic geometry by showing that the H1402A (Kloch et al. 2010) and E1371Q (Vergani et al. 2005) mutations both greatly increase the lifetime of the open state of the CFTR chloride channel, presumably because they block ATP hydrolysis and stabilize ATP-sandwich heterodimer formed by hNBD1 and hNBD2. Login to comment 297 ABCC7 p.His1402Ala ABCC7 p.Glu1371Gln However, despite their similar influence on the gating properties of intact CFTR, the H1402A and E1371Q mutations have dramatically different effects on the stabilityand yield of hNBD2 during purification, with the first greatly improving yield compared to the second (X Zhao, S Atwell, JF Hunt, et al., unpubl.). Login to comment 298 ABCC7 p.His1402Ala ABCC7 p.Glu1371Gln In silico energetic calculations suggest that the H1402A mutation stabilizes isolated hNBD2 bound to Mg-ATP, while the E1371Q mutation destabilizes it (P Kumar, C Wang, JF Hunt, et al., unpubl.). Login to comment