title: A second transient position of ATP on its trail to the nucleotide-binding site of subunit B of the motor protein A(1)A(0) ATP synthase.
abstract: The adenosine triphosphate (ATP) entrance into the nucleotide-binding subunits of ATP synthases is a puzzle. In the previously determined structure of subunit B mutant R416W of the Methanosarcina mazei Gö1 A-ATP synthase one ATP could be trapped at a transition position, close to the phosphate-binding loop. Using defined parameters for co-crystallization of an ATP-bound B-subunit, a unique transition position of ATP could be found in the crystallographic structure of this complex, solved at 3.4 A resolution. The nucleotide is found near the helix-turn-helix motif in the C-terminal domain of the protein; the location occupied by the gamma-subunit to interact with the empty beta-subunit in the thermoalkaliphilic Bacillus sp. TA2.A1 of the related F-ATP synthase. When compared with the determined structure of the ATP-transition position, close to the P-loop, and the nucleotide-free form of subunit B, the C-terminal domain of the B mutant is rotated by around 6 degrees, implicating an ATP moving pathway. We propose that, in the nucleotide empty state the central stalk subunit D is in close contact with subunit B and when the ATP molecule enters, D moves slightly, paving way for it to interact with the subunit B, which makes the C-terminal domain rotate by 6 degrees.
authors.affiliation: Nanyang Technological University, Division of Structural & Computational Biology, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
authors.forename: Malathy Sony Subramanian
authors.initials: MS
authors.lastname: Manimekalai
authors.forename: Anil
authors.initials: A
authors.lastname: Kumar
authors.forename: Asha Manikkoth
authors.initials: AM
authors.lastname: Balakrishna
authors.forename: Gerhard
authors.initials: G
authors.lastname: Grüber
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism*; D019943:Amino Acid Substitution; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D001665:Binding Sites; D003460:Crystallization; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D017434:Protein Structure, Tertiary; D021122:Protein Subunits / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D011994:Recombinant Proteins / Q000737:chemistry; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000737:chemistry / Q000235:genetics
chemical_list: D019843:Archaeal Proteins; D021122:Protein Subunits; D011994:Recombinant Proteins; D014364:Tryptophan; D000255:Adenosine Triphosphate; C113203:A1A0 ATPase, Methanosarcina mazei; D006180:Proton-Translocating ATPases