The Effect of Modifications of the Charged Residues in the Transmembrane Helices on the Transport Activity of the Melibiose Carrier of Escherichia coli

2001 ◽  
Vol 285 (2) ◽  
pp. 348-354 ◽  
Author(s):  
P.Z. Ding ◽  
T.H. Wilson
Keyword(s):  
Escherichia Coli ◽  
Transmembrane Helices ◽  
Transport Activity ◽  
Charged Residues

scholarly journals Clusters of Charged Residues at the C Terminus of MotA and N Terminus of MotB Are Important for Function of the Escherichia coli Flagellar Motor

2008 ◽  
Vol 190 (15) ◽  
pp. 5517-5521 ◽  
Author(s):  
Edan R. Hosking ◽  
Michael D. Manson
Keyword(s):  
Escherichia Coli ◽  
Flagellar Motor ◽  
Protein Levels ◽  
Partner Protein ◽  
C Terminus ◽  
N Terminus ◽  
Charged Residues ◽  
Positively Charged ◽  
Terminal Cluster

ABSTRACT MotA contains a conserved C-terminal cluster of negatively charged residues, and MotB contains a conserved N-terminal cluster of positively charged residues. Charge-altering mutations affecting these residues impair motility but do not diminish Mot protein levels. The motility defects are reversed by second-site mutations targeting the same or partner protein.

scholarly journals Point Mutations in Transmembrane Helices 2 and 3 of ExbB and TolQ Affect Their Activities in Escherichia coli K-12

2004 ◽  
Vol 186 (13) ◽  
pp. 4402-4406 ◽  
Author(s):  
Volkmar Braun ◽  
Christina Herrmann
Keyword(s):  
Escherichia Coli ◽  
Amino Acid ◽  
Transmembrane Helix ◽  
Point Mutations ◽  
Transmembrane Helices ◽  
The Third ◽  
Form Part ◽  
K 12

ABSTRACT Replacement of glutamate 176, the only charged amino acid in the third transmembrane helix of ExbB, with alanine (E176A) abolished ExbB activity in all determined ExbB-dependent functions of Escherichia coli. Combination of the mutations T148A in the second transmembrane helix and T181A in the third transmembrane helix, proposed to form part of a proton pathway through ExbB, also resulted in inactive ExbB. E176 and T148 are strictly conserved in ExbB and TolQ proteins, and T181 is almost strictly conserved in ExbB, TolQ, and MotA.

Structural Role of the First Four Transmembrane Helices in ZntA, a P1B-Type ATPase from Escherichia coli

Biochemistry ◽  
2020 ◽  
Vol 59 (47) ◽  
pp. 4488-4498
Author(s):  
Cameron S. Roberts ◽  
Sandhya Muralidharan ◽  
Fei Ni ◽  
Bharati Mitra
Keyword(s):  
Escherichia Coli ◽  
Transmembrane Helices ◽  
Structural Role
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