Structure of nucleotide-binding domain 1 of the cystic fibrosis transmembrane conductance regulator.
Cystic fibrosis transmembrane conductance regulator (CFTR) is an ATP-binding cassette (ABC) transporter that functions as a chloride channel. Nucleotide-binding domain 1 (NBD1), one of two ABC domains in CFTR, also contains sites for the predominant CF-causing mutation and, potentially, for regulatory phosphorylation. We have determined crystal structures for mouse NBD1 in unliganded, ADP- and ATP-bound states, with and without phosphorylation. This NBD1 differs from typical ABC domains in having added regulatory segments, a foreshortened subdomain interconnection, and an unusual nucleotide conformation. Moreover, isolated NBD1 has undetectable ATPase activity and its structure is essentially the same independent of ligand state. Phe508, which is commonly deleted in CF, is exposed at a putative NBD1-transmembrane interface. Our results are consistent with a CFTR mechanism, whereby channel gating occurs through ATP binding in an NBD1-NBD2 nucleotide sandwich that forms upon displacement of NBD1 regulatory segments.
Lewis
Hal A
HA
Structural GenomiX Inc., San Diego, CA, USA. hal_lewis@stromix.com
Buchanan
Sean G
SG
Burley
Stephen K
SK
Conners
Kris
K
Dickey
Mark
M
Dorwart
Michael
M
Fowler
Richard
R
Gao
Xia
X
Guggino
William B
WB
Hendrickson
Wayne A
WA
Hunt
John F
JF
Kearins
Margaret C
MC
Lorimer
Don
D
Maloney
Peter C
PC
Post
Kai W
KW
Rajashankar
Kanagalaghatta R
KR
Rutter
Marc E
ME
Sauder
J Michael
JM
Shriver
Stephanie
S
Thibodeau
Patrick H
PH
Thomas
Philip J
PJ
Zhang
Marie
M
Zhao
Xun
X
Emtage
Spencer
S
D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism; D000255:Adenosine Triphosphate / Q000737:chemistry* / Q000378:metabolism; D000595:Amino Acid Sequence; D000818:Animals; D001665:Binding Sites; D018360:Crystallography, X-Ray; D019005:Cystic Fibrosis Transmembrane Conductance Regulator / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D051379:Mice; D008958:Models, Molecular; D008969:Molecular Sequence Data; D009154:Mutation; D010766:Phosphorylation; D017434:Protein Structure, Tertiary; D016415:Sequence Alignment
D019005:Cystic Fibrosis Transmembrane Conductance Regulator; D000244:Adenosine Diphosphate; D000255:Adenosine Triphosphate