|Title||Nucleotide-binding sites in V-type Na+-ATPase from Enterococcus hirae.|
|Publication Type||Journal Article|
|Year of Publication||2002|
|Authors||Murata, T, Yoshikawa, Y, Hosaka, T, Takase, K, Kakinuma, Y, Yamato, I, Kikuchi, T|
|Date Published||2002 Nov|
|Keywords||Adenosine Triphosphatases, Amino Acid Sequence, Animals, Binding Sites, Cattle, Enterococcus, Ethylmaleimide, Molecular Sequence Data, Proton-Translocating ATPases, Sodium, Sulfhydryl Reagents, Vacuolar Proton-Translocating ATPases|
Enterococcus hirae V-ATPase, in contrast to most V-type ATPases, is resistant to N-ethylmaleimide (NEM). Alignment of the amino acid sequences of NtpA suggests that the NEM-sensitive Cys of V-type ATPases is replaced by Ala in E. hirae V-ATPase. Consistent with this prediction, the V-ATPase became sensitive upon substitution of the Ala with Cys. The three-dimensional structure of the NtpB subunit of V-ATPase was modeled based on the structure of the corresponding subunit (alpha subunit) of bovine F(1)-ATPase by homology modeling. Overall, the 3D structure of the subunit resembled that of alpha subunit of bovine F(1)-ATPase. The NtpB subunit, which lacks the P-loop consensus sequence for nucleotide binding, was predicted to bind a nucleotide at the modeled nucleotide-binding site. Experimental data supported the prediction that the E. hirae V-ATPase had about six nucleotide-binding sites.
|Alternate Journal||J. Biochem.|