Johann Mertens et al 2012 Nanotechnology 23 015501 doi:10.1088/0957-4484/23/1/015501
Johann Mertens1, María I Daudén2, José L Carrascosa2,3 and Javier Tamayo1
Show affiliationsThe biomolecular machines involved in DNA packaging by viruses generate one of the highest mechanical powers observed in nature. One component of the DNA packaging machinery, called the terminase, has been proposed as the molecular motor that converts chemical energy from ATP hydrolysis into mechanical movement of DNA during bacteriophage morphogenesis. However, the conformational changes involved in this energy conversion have never been observed. Here we report a real-time measurement of ATP-induced conformational changes in the terminase of bacteriophage T7 (gp19). The recording of the cantilever bending during its functionalization shows the existence of a gp19 monolayer arrangement confirmed by atomic force microscopy of the immobilized proteins. The ATP hydrolysis of the gp19 terminase generates a stepped motion of the cantilever and points to a mechanical cooperative effect among gp19 oligomers. Furthermore, the effect of ATP can be counteracted by non-hydrolyzable nucleotide analogs.
87.15.H- Dynamics of biomolecules
87.15.La Mechanical properties
87.15.K- Molecular interactions; membrane-protein interactions
Issue 1 (13 January 2012)
Received 5 September 2011, in final form 31 October 2011
Published 8 December 2011
Johann Mertens et al 2012 Nanotechnology 23 015501
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