Solution structures of the actuator domain of ATP7A and ATP7B, the Menkes and Wilson disease proteins.
ATP7A and ATP7B are two human P(1B)-type ATPases that have a crucial role in maintaining copper(I) homeostasis. Among the various domains of these enzymes, one, called the Actuator or A-domain, has a regulatory function and is required for the phosphatase step of the catalytic cycle (dephosphorylation of the intermediate formed during ATP hydrolysis). Here we report the solution structures of the A-domain of both proteins, solved by heteronuclear NMR spectroscopy and a characterization of the dynamics of the A-domain of ATP7A. We observed that the catalytically important TGE loop protrudes from the structure ready for interaction with the phosphorylated site in the ATP-binding domain. The loop is rigid, suggesting that the catalytic step does not require substantial structural flexibility or rearrangements. The present structures were useful to rationalize the molecular effects of disease-causing mutations. In particular, it can be concluded that mutations occurring in the A-domain either destabilize the fold of the domain (such as Gly860Val in ATP7A) or affect the network of communication within the domain (such as Leu873Arg in ATP7A) or with the other domains of the enzyme (such as Gly853Arg in ATP7A).
Banci
Lucia
L
Magnetic Resonance Center (CERM)-University of Florence, Via L. Sacconi 6, 50019 Sesto Fiorentino, Italy.
Bertini
Ivano
I
Cantini
Francesca
F
Migliardi
Manuele
M
Natile
Giovanni
G
Nushi
Fiorentin
F
Rosato
Antonio
A
D000251:Adenosine Triphosphatases / Q000737:chemistry* / Q000235:genetics; D000595:Amino Acid Sequence; D002384:Catalysis; D027682:Cation Transport Proteins / Q000737:chemistry* / Q000235:genetics; D003300:Copper / Q000378:metabolism; D000073840:Copper-Transporting ATPases; D018360:Crystallography, X-Ray; D006527:Hepatolenticular Degeneration / Q000201:enzymology* / Q000235:genetics; D006706:Homeostasis / Q000235:genetics; D006801:Humans; D007706:Menkes Kinky Hair Syndrome / Q000201:enzymology* / Q000235:genetics; D008969:Molecular Sequence Data; D020125:Mutation, Missense; D017510:Protein Folding; D055550:Protein Stability; D017434:Protein Structure, Tertiary / Q000235:genetics; D017386:Sequence Homology, Amino Acid; D012996:Solutions
D027682:Cation Transport Proteins; D012996:Solutions; D003300:Copper; D000251:Adenosine Triphosphatases; C081184:ATP7A protein, human; C000612464:ATP7B protein, human; D000073840:Copper-Transporting ATPases