scholarly journals Cysteine Scanning of CFTR’s First Transmembrane Segment Reveals Its Plausible Roles in Gating and Permeation

2013 ◽  
Vol 104 (4) ◽  
pp. 786-797 ◽  
Author(s):  
Xiaolong Gao ◽  
Yonghong Bai ◽  
Tzyh-Chang Hwang
Keyword(s):  
Transmembrane Segment ◽  
Cysteine Scanning

Determination of a Transmembrane Segment Using Cysteine-Scanning Mutants of Transposon Tn10-Encoded Metal−Tetracycline/H+Antiporter†

Biochemistry ◽  
1996 ◽  
Vol 35 (49) ◽  
pp. 15896-15899 ◽  
Author(s):  
Tomomi Kimura ◽  
Masayo Suzuki ◽  
Tetsuo Sawai ◽  
Akihito Yamaguchi
Keyword(s):  
Transmembrane Segment ◽  
Cysteine Scanning

scholarly journals Cysteine-scanning mutagenesis around transmembrane segment VI of Tn10-encoded metal-tetracycline/H+ antiporter

FEBS Letters ◽  
1999 ◽  
Vol 461 (3) ◽  
pp. 315-318 ◽  
Author(s):  
Satoko Konishi ◽  
Shinobu Iwaki ◽  
Tomomi Kimura-Someya ◽  
Akihito Yamaguchi
Keyword(s):  
Transmembrane Segment ◽  
Cysteine Scanning ◽  
Cysteine Scanning Mutagenesis

scholarly journals Cysteine-scanning Mutagenesis around Transmembrane Segment III of Tn10-encoded Metal-Tetracycline/H+Antiporter

1998 ◽  
Vol 273 (9) ◽  
pp. 5243-5247 ◽  
Author(s):  
Tomomi Kimura ◽  
Yasuko Shiina ◽  
Tetsuo Sawai ◽  
Akihito Yamaguchi
Keyword(s):  
Transmembrane Segment ◽  
Cysteine Scanning ◽  
Cysteine Scanning Mutagenesis

scholarly journals Cysteine-Scanning Mutagenesis of the Periplasmic Loop Regions of PomA, a Putative Channel Component of the Sodium-Driven Flagellar Motor in Vibrio alginolyticus

2000 ◽  
Vol 182 (4) ◽  
pp. 1001-1007 ◽  
Author(s):  
Yukako Asai ◽  
Tomokazu Shoji ◽  
Ikuro Kawagishi ◽  
Michio Homma
Keyword(s):  
Structure And Function ◽  
Vibrio Alginolyticus ◽  
Membrane Topology ◽  
Flagellar Motor ◽  
Transmembrane Segment ◽  
Transmembrane Segments ◽  
Cysteine Scanning ◽  
Loop Regions ◽  
Cysteine Scanning Mutagenesis ◽  
And Function

ABSTRACT The sodium-driven motor consists of the products of at least four genes, pomA, pomB, motX, andmotY, in Vibrio alginolyticus. PomA and PomB, which are homologous to the MotA and MotB components of proton-driven motors, have four transmembrane segments and one transmembrane segment, respectively, and are thought to form an ion channel. In PomA, two periplasmic loops were predicted at positions 21 to 36 between membrane segments 1 and 2 (loop1-2) and at positions 167 to 180 between membrane segments 3 and 4 (loop3-4). To characterize the two periplasmic loop regions, which may have a role as an ion entrance for the channel, we carried out cysteine-scanning mutagenesis. The T186 residue in the fourth transmembrane segment and the D71, D148, and D202 residues in the predicted cytoplasmic portion of PomA were also replaced with Cys. Only two mutations, M179C and T186C, conferred a nonmotile phenotype. Many mutations in the periplasmic loops and all of the cytoplasmic mutations did not abolish motility, though the five successive substitutions from M169C to K173C of loop3-4 impaired motility. In some mutants that retained substantial motility, motility was inhibited by the thiol-modifying reagents dithionitrobenzoic acid and N-ethylmaleimide. The profiles of inhibition by the reagents were consistent with the membrane topology predicted from the hydrophobicity profiles. Furthermore, from the profiles of labeling by biotin maleimide, we predicted more directly the membrane topology of loop3-4. None of the loop1-2 residues were labeled, suggesting that the environments around the two loops are very different. A few of the mutations were characterized further. The structure and function of the loop regions are discussed.

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