page_title: List of biophysicists
section_title: B
hierarchical_section_title: List of biophysicists / B
caption_attribution_description: English: Air date: Wednesday, September 07, 2011, 3:00:00 PM Time displayed is Eastern Time, Washington DC Local Category: Wednesday Afternoon Lectures Description: As part of their infection cycle, many viruses must package their newly replicated genomes inside a protein capsid to insure its proper transport and delivery to other host cells. Bacteriophage phi29 packages its 6.6 mm long double-stranded DNA into a 42 nm dia. x 54 nm high capsid using a multimeric ring motor that belongs to the ASCE (Additional Strand, Conserved E) superfamily of ATPases. A number of fundamental questions remain as to the coordination of the various subunits in these multimeric rings. The portal motor in phi29 is ideal to investigate these questions. Using optical tweezers, we find that this motor can work against loads of up to ~57 picoNewtons on average, making it one of the strongest molecular motors ever reported. Interestingly, the packaging rate decreases as the prohead is filled, indicating that an internal pressure builds up due to DNA compression. The capsid pressure at the end of the packaging is ~6 MegaPascals, corresponding to an internal force of ~52 pN acting on the motor. We have identified where in the mechanochemical cycle the chemical energy of ATP is converted into mechanical work. Using ultra-high resolution optical tweezers, we have performed the first direct measurement of the step size of a translocating ring ATPase. What emerges is a surprising mechanism that involves a step size with a non-integer number of base pairs and that reveals an unexpected degree of coordination among the individual subunits that has not been proposed previously for a ring ATPase. For more information, visit: The NIH Director's Wednesday Afternoon Lecture Series Author: Dr. Carlos J. Bustamante Runtime: 01:10:39 Download: Download Video How to download a Videocast Caption Text: Download Caption File CIT File ID: 16822 CIT Live ID: 10500 Permanent link: http://videocast.nih.gov/launch.asp?16822
context_page_description: This is a list of persons known for their research in biophysics.
context_section_description: Robert L. (Buzz) Baldwin — protein folding
  David Baker — Protein structure prediction; protein design; Rosetta software
  Adriaan (Ad) Bax (Dutch-born American, 1956–) — development of methodology for NMR (Nuclear magnetic resonance) spectroscopy
  Georg von Békésy (Hungarian, 1899–1972) — research on the human ear
  Boris Pavlovich Belousov — known for discovery of Belousov–Zhabotinsky reaction
  Howard Berg (American, 1934–) — characterized properties of bacterial chemotaxis
  Helen M. Berman (American, 1943–) — pioneer in study of nucleic acid structure; head of the worldwide Protein Data Bank
  John Desmond Bernal (Irish-born English, 1901–1971) — X-ray crystallography of plant viruses and proteins
  Pamela J. Bjorkman (American, 1956–) — first X-ray crystallography of human histocompatibility complex; studies immune recognition, homologs of MHC proteins, and improved antibodies against HIV
  Steven Block (American, 1952–) — observed the motions of enzymes such as kinesin and RNA polymerase with optical tweezers
  Sir Tom Blundell — crystal structures of HIV protease, renin, insulin and other hormones, growth factors, receptors, and proteins important in cell signalling and DNA repair; developed structure-guided and fragment-based approaches to drug design
  Jagadish Chandra Bose (Indian, 1858–1937)
  Detlev Wulf Bronk (American, 1897–1975) 
  Axel Brunger — developed the free R cross-validation index and the X-PLOR/CNS software for macromolecular crystallography
  Carlos Bustamante (Peruvian-born American, 1951–) —  known for single-molecule biophysics of molecular motors and biological polymer physics
caption: Carlos Bustamante
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