Spectroscopic and crystallographic studies of the mutant R416W give insight into the nucleotide binding traits of subunit B of the A1Ao ATP synthase.
A strategically placed tryptophan in position of Arg416 was used as an optical probe to monitor adenosine triphosphate and adenosine-diphosphate binding to subunit B of the A(1)A(O) adenosine triphosphate (ATP) synthase from Methanosarcina mazei Gö1. Tryptophan fluorescence and fluorescence correlation spectroscopy gave binding constants indicating a preferred binding of ATP over ADP to the protein. The X-ray crystal structure of the R416W mutant protein in the presence of ATP was solved to 2.1 A resolution, showing the substituted Trp-residue inside the predicted adenine-binding pocket. The cocrystallized ATP molecule could be trapped in a so-called transition nucleotide-binding state. The high resolution structure shows the phosphate residues of the ATP near the P-loop region (S150-E158) and its adenine ring forms pi-pi interaction with Phe149. This transition binding position of ATP could be confirmed by tryptophan emission spectra using the subunit B mutant F149W. The trapped ATP position, similar to the one of the binding region of the antibiotic efrapeptin in F(1)F(O) ATP synthases, is discussed in light of a transition nucleotide-binding state of ATP while on its way to the final binding pocket. Finally, the inhibitory effect of efrapeptin C in ATPase activity of a reconstituted A(3)B(3)- and A(3)B(R416W)(3)-subcomplex, composed of subunit A and the B subunit mutant R416W, of the A(1)A(O) ATP synthase is shown.
Kumar
Anil
A
Division of Structural and Computational Biology, Nanyang Technological University, School of Biological Sciences, 60 Nanyang Drive, Singapore 637551, Republic of Singapore.
Manimekalai
Malathy Sony Subramanian
MS
Balakrishna
Asha Manikkoth
AM
Hunke
Cornelia
C
Weigelt
Sven
S
Sewald
Norbert
N
Grüber
Gerhard
G
D000244:Adenosine Diphosphate / Q000737:chemistry / Q000378:metabolism*; D000255:Adenosine Triphosphate / Q000737:chemistry / Q000378:metabolism*; D019943:Amino Acid Substitution; D019843:Archaeal Proteins / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D018360:Crystallography, X-Ray; D008958:Models, Molecular; D009711:Nucleotides / Q000737:chemistry / Q000378:metabolism; D021122:Protein Subunits / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D006180:Proton-Translocating ATPases / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism*; D013050:Spectrometry, Fluorescence; D014364:Tryptophan / Q000378:metabolism
D019843:Archaeal Proteins; D009711:Nucleotides; D021122:Protein Subunits; D000244:Adenosine Diphosphate; D014364:Tryptophan; D000255:Adenosine Triphosphate; C113203:A1A0 ATPase, Methanosarcina mazei; D006180:Proton-Translocating ATPases