2VHU

P4 PROTEIN FROM BACTERIOPHAGE PHI12 K241C mutant in complex with ADP and MgCl

Summary for 2VHU

• Entry DOI: 10.2210/pdb2vhu/pdb
• Related: 1W44 1W46 1W47 1W48 1W49 1W4A 1W4B 1W4C 2VHC 2VHJ 2VHQ 2VHT
• Descriptor: NTPASE P4, ADENOSINE-5'-DIPHOSPHATE, MAGNESIUM ION, ... (4 entities in total)
• Functional Keywords: virus dsrna, hydrolase, molecular motor, packaging atpase, hexameric helicase, non-hydrolysable atp analogue
• Biological source: PSEUDOMONAS PHAGE PHI12 (BACTERIOPHAGE PHI12)
• Total number of polymer chains: 3
• Total formula weight: 106727.70

Authors

Kainov, D.E.,Mancini, E.J.,Telenius, J.,Lisal, J.,Grimes, J.M.,Bamford, D.H.,Stuart, D.I.,Tuma, R. (deposition date: 2007-11-25, release date: 2007-12-11, Last modification date: 2024-05-08)

Primary citation

Kainov, D.E.,Mancini, E.J.,Telenius, J.,Lisal, J.,Grimes, J.M.,Bamford, D.H.,Stuart, D.I.,Tuma, R.
Structural Basis of Mechanochemical Coupling in a Hexameric Molecular Motor.
J.Biol.Chem., 283:3607-, 2008

PubMed Abstract: The P4 protein of bacteriophage phi12 is a hexameric molecular motor closely related to superfamily 4 helicases. P4 converts chemical energy from ATP hydrolysis into mechanical work, to translocate single-stranded RNA into a viral capsid. The molecular basis of mechanochemical coupling, i.e. how small approximately 1 A changes in the ATP-binding site are amplified into nanometer scale motion along the nucleic acid, is not understood at the atomic level. Here we study in atomic detail the mechanochemical coupling using structural and biochemical analyses of P4 mutants. We show that a conserved region, consisting of superfamily 4 helicase motifs H3 and H4 and loop L2, constitutes the moving lever of the motor. The lever tip encompasses an RNA-binding site that moves along the mechanical reaction coordinate. The lever is flanked by gamma-phosphate sensors (Asn-234 and Ser-252) that report the nucleotide state of neighboring subunits and control the lever position. Insertion of an arginine finger (Arg-279) into the neighboring catalytic site is concomitant with lever movement and commences ATP hydrolysis. This ensures cooperative sequential hydrolysis that is tightly coupled to mechanical motion. Given the structural conservation, the mutated residues may play similar roles in other hexameric helicases and related molecular motors.

PubMed: 18057007
DOI: 10.1074/JBC.M706366200

Experimental method

X-RAY DIFFRACTION (2.75 Å)