ABCMdb

ABCC7 p.Gln98Lys

ClinVar:	c.293A>G , p.Gln98Arg ? , not provided c.292C>T , p.Gln98* D , Pathogenic c.293A>C , p.Gln98Pro ? , not provided
CF databases:	c.293A>C , p.Gln98Pro (CFTR1) D , This mutation was found by DHPLC and confirmed by sequencing. The adult male patient, from Southern Sweden, carries deltaF508 on the other chromosome. The patient has high sweat chloride (116 mmol/L), bronchiectasis and CBAVD. c.292C>T , p.Gln98* D , CF-causing c.293A>G , p.Gln98Arg (CFTR1) D , This mutation was found in one CF patient from Southern France, who carries [delta]F508 on the other gene. It creates a HaeIII restriction site (N : 290 +78 +70 bp), (m: 153 + 137 + 78 + 70 bp) when using the primers 4i5/4i3 from Zielinski. Also reported by Yoshimura & Azuma on 4/01/1000: This mutation was detected in one of the CFTR alleles of a 15-year old Japanese male patient with cystic fibrosis. He is pancreatic insufficient, has CBAVD, and his sweat chloride was high (74 mmol/L). Another mutation was not found despite the thorough evaluation for his entire 27 exons of the CFTR gene. Interestingly, he was heterozygous at the cDNA 125 in 5'UTR (i.e., 125G/125C), and this is the only difference from his healthy sister who is also heterozygous for Q98R mutation, but 125G/125G, suggesting that 125C may be disease-causing.
Predicted by SNAP2:	A: D (95%), C: D (95%), D: D (95%), E: D (95%), F: D (95%), G: D (95%), H: D (95%), I: D (95%), K: D (95%), L: D (95%), M: D (95%), N: D (95%), P: D (95%), R: N (78%), S: D (95%), T: D (95%), V: D (95%), W: D (95%), Y: D (95%),
Predicted by PROVEAN:	A: D, C: D, D: D, E: N, F: D, G: D, H: D, I: D, K: N, L: D, M: D, N: N, P: D, R: N, S: N, T: D, V: D, W: D, Y: D,

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Publications
[hide] Tuning of CFTR chloride channel function by locati... Biophys J. 2012 Oct 17;103(8):1719-26. doi: 10.1016/j.bpj.2012.09.020. Epub 2012 Oct 16. El Hiani Y, Linsdell P
Tuning of CFTR chloride channel function by location of positive charges within the pore.
Biophys J. 2012 Oct 17;103(8):1719-26. doi: 10.1016/j.bpj.2012.09.020. Epub 2012 Oct 16., [PMID:23083715]

Abstract [show]
High unitary Cl(-) conductance in the cystic fibrosis transmembrane conductance regulator Cl(-) channel requires a functionally unique, positively charged lysine residue (K95) in the inner vestibule of the channel pore. Here we used a mutagenic approach to investigate the ability of other sites in the pore to host this important positive charge. The loss of conductance observed in the K95Q mutation was >50% rescued by substituting a lysine for each of five different pore-lining amino acids, suggesting that the exact location of the fixed positive charge is not crucial to support high conductance. Moving the positive charge also restored open-channel blocker interactions that are lost in K95Q. Introducing a second positive charge in addition to that at K95 did not increase conductance at any site, but did result in a striking increase in the strength of block by divalent Pt(NO(2))(4)(2-) ions. Based on the site dependence of these effects, we propose that although the exact location of the positive charge is not crucial for normal pore properties, transplanting this charge to other sites results in a diminution of its effectiveness that appears to depend on its location along the axis of the pore.

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49 conductance (Fig. 2, B and C), especially in Q98K (conductance 75 5 1% of WT, n &#bc; 6) and V345K (64 5 3% of WT, n &#bc; 9), and in no case was conductance increased by the addition of a second positive charge. Login to comment
55 Additional mutations in a K95Q background to transplant the positive charge to pore-lining positions in TM1 (Q98K) or TM6 (I344K, V345K, M348K, and A349K) partially restored NPPB block (Fig. 3), although in no case was the block as strong as for the WT. Login to comment
56 The rank order of the apparent strength of NPPB block was WT > K95Q/V345K > K95Q/I344K > K95Q/Q98K ~ K95Q/ M348K ~ K95Q/A349K (Fig. 3 B). Login to comment
60 As shown in Fig. 4, block by Pt(NO2)4 2 was significantly strengthened in each of the mutants Q98K, I344K, V345K, M348K, and A349K, as well as in the previously unstudied S341K. Login to comment
61 At 0 mV membrane potential, the apparent Kd for Pt(NO2)4 2 block was in the rank order V345K (3.3 5 0.9 mM, n &#bc; 7) % I344K (4.5 5 0.7 mM, n &#bc; 6) < S341K (26.6 5 1.8 mM, n &#bc; 7) < M348K (80.9 5 7.2 mM, n &#bc; 5) % Q98K (95.4 5 11.0 mM, n &#bc; 6) % A349K (117.4 5 7.7 mM, FIGURE 2 Single-channel conductance is restored by moving the positive charge from K95. Login to comment
74 Blocker voltage dependence was also significantly changed in most mutants, with the effective blocker valence (zd) being significantly increased in M348K and significantly decreased in Q98K, V345K, and A349K (Fig. 4 F). Login to comment
90 However, although a single positive charge is necessary, the addition of a second positive charge to this region of the pore (as in the point mutants Q98K, I344K, V345K, M348K, and A349K) failed to increase conductance above WT levels (Fig. 2), as previously observed for S1141K (8). Login to comment
99 In fact, the addition of a second positive charge in Q98K, I344K, V345K, M348K, and A349K led to a small, but significant, decrease in conductance (Fig. 2 C). Login to comment
105 The weakening of blocker binding seen in K95Q is partially reversed by the second site mutations I344K and V345K, and to a lesser extent Q98K, M348K, and A349K. Login to comment
146 Again this appears to be a relatively nonsite-specific effect of positive charge, since all mutants studied (Q98K, S341K, I344K, V345K, M348K, and A349K) led to significant increase in apparent affinity of Pt(NO2)4 2 block (Fig. 4), as did S1141K (8). Login to comment