The Amt/MEP/Rh family: structure of AmtB and the mechanism of ammonia gas conduction.
The atomic structures of the first members of the Amt/MEP/Rh family show that they are 11-crossing membrane proteins that form trimers in the membrane. Each monomer supports a hydrophobic channel that conducts NH(3) but not any water or ions. The reprotonation of NH(3) on the receiving side raises the pH on that side in the absence of metabolism of NH(3), and there is no transfer of protons through the protein.
Khademi
Shahram
S
Department of Biochemistry and Biophysics, University of California-San Francisco, San Francisco, California, USA.
Stroud
Robert M
RM
D000595:Amino Acid Sequence; D000641:Ammonia / Q000378:metabolism*; D000818:Animals; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029968:Escherichia coli Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D005740:Gases; D006801:Humans; D008969:Molecular Sequence Data; D011487:Protein Conformation; D012204:Rh-Hr Blood-Group System / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism
C111096:AmtB protein, E coli; D027682:Cation Transport Proteins; D029968:Escherichia coli Proteins; D005740:Gases; C107270:MEP2 protein, S cerevisiae; D012204:Rh-Hr Blood-Group System; D029701:Saccharomyces cerevisiae Proteins; D000641:Ammonia