Cystic fibrosis-associated mutations at arginine 347 alter the pore architecture of CFTR - Evidence for disruption of a salt bridge
Cystic fibrosis-associated mutations at arginine 347 alter the pore architecture of CFTR - Evidence for disruption of a salt bridge
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DOI：
10.1074/jbc.274.9.5429
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发表时间：
1999-02-26
影响因子：
4.8
通讯作者：
Welsh, MJ
中科院分区：
文献类型：
--
作者：
Cotten, JF;Welsh, MJ
Arginine 347 in the sixth transmembrane domain of cystic fibrosis transmembrane conductance regulator (CFTR) is a site of four cystic fibrosis-associated mutations. To better understand the function of Arg-347 and to learn how mutations at this site disrupt channel activity, we mutated Arg-347 to Asp, Cys, Glu, His, Leu, or Lys and examined single-channel function. Every Arg-347 mutation examined, except R347K, had a destabilizing effect on the pore, causing the channel to flutter between two conductance states. Chloride flow through the larger conductance state was similar to that of wildtype CFTR, suggesting that the residue at position 347 does not interact directly with permeating anions, We hypothesized that Arg-347 stabilizes the channel through an electrostatic interaction with an anionic residue in another transmembrane domain. To test this, we mutated anionic residues (Asp-924, Asp-993, and Glu-1104) to Arg in the context of either R347E or R347D mutations. Interestingly, the D924R mutation complemented R347D, yielding a channel that behaved Like wild-type CFTR, These data suggest that Arg-347 plays an important structural role in CFTR, at least in part by forming a salt bridge with Asp-924; cystic fibrosis-associated mutations disrupt this interaction.
