ISDA

Deposition Date 2004-08-03

Release Date 2004-09-21

Last Version Date 2024-10-16

Entry Detail

PDB ID:

1U7G

Keywords:

TRANSPORT PROTEIN

Title:

Crystal Structure of Ammonia Channel AmtB from E. Coli

Biological Source:

Source Organism:

Escherichia coli (Taxon ID: 562)

Host Organism:

Escherichia coli

Method Details:

Experimental Method:

X-RAY DIFFRACTION

Resolution:

1.40 Å

R-Value Free:

0.16

R-Value Work:

0.13

R-Value Observed:

0.13

Space Group:

P 63

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Macromolecular Entities

Protein Blast

Polymer Type:polypeptide(L)
Molecule:Probable ammonium transporter
Gene (Uniprot):amtB
Mutations:S68F,P126S,L255K
Chain IDs:A
Chain Length:385
Number of Molecules:1
Biological Source:Escherichia coli

UniProt ID:P69681 Pfam ID:PF00909

Modified Residue

Compound ID	Chain ID	Parent Comp ID	Details	2D Image
MSE	A	MET	SELENOMETHIONINE

Ligand Molecules

BOG

NH3

NH4

Primary Citation

Mechanism of ammonia transport by Amt/MEP/Rh: structure of AmtB at 1.35 A

Khademi, S, O'Connell III, J, Remis, J, Robles-Colmenares, Y, Miercke, L.J.W, Stroud, R.M.Show

Science 305 1587 1594 (2004)

PMID: 15361618 DOI: 10.1126/science.1101952

Abstact

The first structure of an ammonia channel from the Amt/MEP/Rh protein superfamily, determined to 1.35 angstrom resolution, shows it to be a channel that spans the membrane 11 times. Two structurally similar halves span the membrane with opposite polarity. Structures with and without ammonia or methyl ammonia show a vestibule that recruits NH4+/NH3, a binding site for NH4+, and a 20 angstrom-long hydrophobic channel that lowers the NH4+ pKa to below 6 and conducts NH3. Favorable interactions for NH3 are seen within the channel and use conserved histidines. Reconstitution of AmtB into vesicles shows that AmtB conducts uncharged NH3.

Legend

Protein

Chemical

Disease

Primary Citation of related structures