Isolated noncatalytic and catalytic subunits of F<sub>1sub>-ATPase exhibit similar, albeit not identical, energetic strategies for recognizing adenosine nucleotides

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• 作者：Guillermo Salcedo ; Patricia Cano-S谩nchez ; Marietta Tuena de G贸mez-Puyou ; Adri谩n Vel谩zquez-Campoy ; Enrique Garc铆a-Hern谩ndez
• 关键词：Mg(II) ; free magnesium ion ; ATP ; adenosine 5&prime ; -triphosphate ; ADP ; adenosine 5&prime ; -diphosphate ; EDTA ; ethylenediaminetetraacetic acid ; Tris ; 2-amino-2-(hydroxymethyl)propane-1 ; 3-diol ; MgCl2 ; magnesium chloride ; ATPase ; adenosine 5&prime ; -triphosphatase ; TF1 ; F1 sector from Bacillus PS3 ; EF1 ; F1 sector from Escherichia coli ; S1 ; S2 and S3 ; high ; medium and low affinity 尾-subunit sites in F1 ; respectively ; 尾DP and 尾TP ; 尾 subunits in the crystal structure of F1 bound to Mg· ; ADP and
• 刊名：Biochimica et Biophysica Acta (BBA)/Bioenergetics
• 出版年：January, 2014
• 年：2014
• 卷：1837
• 期：1
• 页码：44-50
• 全文大小：728 K

文摘

The function of F<sub>1sub>-ATPase relies critically on the intrinsic ability of its catalytic and noncatalytic subunits to interact with nucleotides. Therefore, the study of isolated subunits represents an opportunity to dissect elementary energetic contributions that drive the enzyme's rotary mechanism. In this study we have calorimetrically characterized the association of adenosine nucleotides to the isolated noncatalytic 伪-subunit. The resulting recognition behavior was compared with that previously reported for the isolated catalytic 尾-subunit (N.O. Pulido, G. Salcedo, G. P茅rez-Hern谩ndez, C. Jos茅-N煤帽ez, A. Vel谩zquez-Campoy, E. Garc铆a-Hern谩ndez, Energetic effects of magnesium in the recognition of adenosine nucleotides by the F<sub>1sub>-ATPase 尾 subunit, Biochemistry 49 (2010) 5258-5268). The two subunits exhibit nucleotide-binding thermodynamic signatures similar to each other, characterized by enthalpically-driven affinities in the 渭M range. Nevertheless, contrary to the catalytic subunit that recognizes MgATP and MgADP with comparable strength, the noncatalytic subunit much prefers the triphosphate nucleotide. Besides, the 伪-subunit depends more on Mg(II) for stabilizing the interaction with ATP, while both subunits are rather metal-independent for ADP recognition. These binding behaviors are discussed in terms of the properties that the two subunits exhibit in the whole enzyme.