ABCMdb

ABCC7 p.Gln237Leu

ClinVar:	c.709C>G , p.Gln237Glu ? , not provided c.711G>C , p.Gln237His ? , not provided
CF databases:	c.709C>G , p.Gln237Glu (CFTR1) ? , The substitution was founf in an adult patient presenting with chronic pulmonary infections and a positive sweat chloride test. c.711G>C , p.Gln237His (CFTR1) ? ,
Predicted by SNAP2:	A: D (71%), C: D (66%), D: D (80%), E: D (71%), F: D (80%), G: D (75%), H: D (75%), I: D (75%), K: D (85%), L: D (80%), M: D (71%), N: D (66%), P: D (85%), R: D (66%), S: D (66%), T: D (66%), V: D (71%), W: D (85%), Y: D (75%),
Predicted by PROVEAN:	A: D, C: D, D: N, E: N, F: D, G: D, H: N, I: D, K: N, L: D, M: N, N: N, P: D, R: N, S: N, T: N, V: D, W: D, Y: D,

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Publications
[hide] Positional dependence of non-native polar mutation... Biochim Biophys Acta. 2008 Jan;1778(1):79-87. Epub 2007 Sep 15. Wehbi H, Gasmi-Seabrook G, Choi MY, Deber CM
Positional dependence of non-native polar mutations on folding of CFTR helical hairpins.
Biochim Biophys Acta. 2008 Jan;1778(1):79-87. Epub 2007 Sep 15., [PMID:17949679]

Abstract [show]
Mutations of the cystic fibrosis transmembrane conductance regulator (CFTR) cause CF disease by altering the biosynthesis, maturation, folding and ion conductance of this protein. Our laboratory has focused on expression and structural analysis of the CFTR transmembrane (TM) domains using two-TM segments (i.e., helix-loop-helix constructs) which we term 'helical hairpins'; these represent the minimal model of tertiary contacts between two helices in a membrane. Previous studies on a library of TM3/4 hairpins of the first CFTR TM domain suggested that introduction of non-native polar residues into TM4 can compromise CFTR function through side chain-side chain H-bonding interactions with native Q207 in TM3 [Choi, M. Y., Cardarelli, L., Therien, A. G., and Deber, C. M. Non-native interhelical hydrogen bonds in the cystic fibrosis transmembrane conductance regulator domain modulated by polar mutations, Biochemistry 43 (2004) 8077-8083]. In the present work, we combine gel shift assays with a series of NMR experiments for comparative structural characterization of the wild type TM3/4 hairpin and its mutants V232D, I231D, Q207N/V232E. Over 95% of the backbone resonances of a 15N,13C-labelled V232D-TM3/4 construct in the membrane-mimetic environment of perfluorooctanoate (PFO) micelles were successfully assigned, and the presence and boundaries of helical segments within TM3 and TM4 were defined under these conditions. Comparative analysis of 15N and 1H chemical shift variations among HSQC spectra of WT-, V232D-, I231D- and Q207N/V232E-TM3/4 indicated that hairpin conformations vary with the position of a polar mutation (i.e., V232D and I231D vs. WT), but remain similar when hairpins with identically-positioned polar partners are compared (i.e., V232D vs. Q207N-V232E). The overall findings suggest that a polar mutation in a TM helix can potentially distort native interfacial packing determinants in membrane proteins such as CFTR, with consequences that may lead to disease.

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95 In contrast, replacement of wild type Q237 in TM4 with the non-polar Leu residue (mutant Q237L) creates a slower migrating hairpin vs. wild type (Fig. 1a), suggesting that some pre-existing inter-helical interactions - conceivably attributable to a network of H-bonding interactions - have been removed. Login to comment
96 The helix-helix interactions influenced by polar mutants among the positions studied are summarized in Fig. 1b, where it is seen that constructs involving I231 and V232 with combinations of TM4 D-mutations, as well as various combinations of Q207N with D and E mutants in TM4, migrate between 7 and 20% faster than the WT construct. Login to comment
123 (a) Relative migration rates of wild type CFTR TM3/4 and mutants Q237L and Q207N-V232E. Login to comment
124 (a) Relative migration rates of wild type CFTR TM3/4 and mutants Q237L and Q207N-V232E. Login to comment

[hide] Non-native interhelical hydrogen bonds in the cyst... Biochemistry. 2004 Jun 29;43(25):8077-83. Choi MY, Cardarelli L, Therien AG, Deber CM
Non-native interhelical hydrogen bonds in the cystic fibrosis transmembrane conductance regulator domain modulated by polar mutations.
Biochemistry. 2004 Jun 29;43(25):8077-83., [PMID:15209503]

Abstract [show]
Polar residues comprise about 15% of the transmembrane (TM) domains of proteins, where they can stabilize structure via native side chain-side chain interhelical hydrogen bonds between TM helices. However, non-native H-bonds may be implicated in disease states, through limiting protein dynamics during transport and/or misfolding the protein by inducing non-native rotational positions about TM helical axes. Here we have undertaken an investigation of the presence and strength of H-bond interactions within a series of helix-loop-helix ("hairpin") constructs derived from TM helices 3 and 4 (italic) of the cystic fibrosis transmembrane conductance regulator (CFTR) (prototypic sequence G(194)LALAHFVWIAPLQ(207)VALLMGLIWELLQASAFAGLGFLIV(232)LALFQ(237)AGLG(241)) in which wild-type Q207 in TM3 forms an interhelical H-bond with CF-phenotypic mutant V232D in TM4 [Therien, A. G., Grant, F. E., and Deber, C. M. (2001) Nat. Struct. Biol 8, 597-601]. In the present work, a library of 21 TM3/4 constructs was prepared, where Asp residues were placed individually at TM4 positions 221-241. Using gel shift assays-in which H-bond-linked hairpins (closed conformation) migrate faster than the elongated forms (open conformation)-we found that Q207 in TM3 is able to "capture" all 21 TM4 D mutations into measurable populations of interhelical H-bonds. A similar library of TM4 D mutants-but also containing Q207L-reverted to wild-type migration rates, confirming Q207 as the polar partner for TM4 D residues. In view of the broad capture range of Q207, these results emphasize the potential consequences to folding and dynamics of introducing polar mutations into the TM domains of membrane proteins in the vicinity of a native polar TM residue.

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No. Sentence Comment
118 Figure 5 displays the comparison of the migration differences on SDS-PAGE between six X f D mutants and their Q237L counterparts in the CFTR TM3/4 construct. Login to comment
119 Our results indicate a discrete role for Q237, viz., the double mutants F224D/ Q237L, A238D/Q237L and G239D/Q237Lsin which the D locus is nearer to the Nor C-terminus of the TM4 helixs returned to the wt migration rate. Login to comment
120 D mutants in mid-TM4, i.e., V232D/Q237L and L230D/Q237L, continued to migrate faster than the wt, but were clearly retarded vs their D counterparts. Login to comment
141 FIGURE 5: Comparison of relative migration rates on SDS-PAGE (NuPAGE MES gel system) for X f D mutants and selected XD/ Q237L mutants in CFTR TM3/4 constructs. Login to comment
178 From the results (Figures 5 and 7), we found that double mutants where D is relatively distant from Q207 in TM3 (F224D/ Q237L, A238D/Q237L, and G239D/Q237L) returned to the wt migration rate, whereas the other double mutants (V232D/ Q237L and L230D/Q237L) migrated more slowly than the corresponding D mutants, but still significantly faster than the wt construct. Login to comment