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Energy Conversion in Biology

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Air date: Wednesday, April 25, 2007, 1:00:00 PM
Time displayed is Eastern Time, Washington DC Local
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Category: WALS - Wednesday Afternoon Lectures
Runtime: 01:06:01
Description: Special 1:00 PM Director's Wednesday Afternoon Lecture

Modern oxygen evolving photosynthesis requires more than 200 proteins. Many of them are organised in highly complex structures in the chloroplasts of green plants (and also in cyanobacteria) where incident light energy from the sun is entrapped in the carbohydrates and fats that provide our food with calorific value. We release the energy by respiration (controlled burning), consuming in the process most of the oxygen that we have breathed in. Of the 1000 or so proteins that are involved, about 100 of them are organised into the respiratory enzyme complexes in mitochondria that function as molecular machines to convert the redox energy derived from food-stuffs into adenosine triphosphate (ATP), the energy currency of biology. The final synthetic step is achieved by a remarkable molecular machine that has a mechanical rotary action. Its closest man-made analogue is the Wankel rotary engine. Its workings will be described and how such complex machines evolve will be discussed.

Professor John Walker FRS is Director of the Medical Research Council Dunn Human Nutrition Unit in Cambridge, UK, since 1998. In 1974 he was recruited by Fred Sanger to the Laboratory of Molecular Biology in Cambridge, UK, and early on he helped to uncover details of the modified genetic code of mitochondrial DNA. In 1978 he began studying the ATP synthase from mitochondria and from bacteria, resulting in a complete sequence analysis of this complex enzyme from several species. This was the ouverture to his work leading, in 1994, to the resolution of the 3D structure of the headpiece and stalk of this remarkable energy transducer by X-ray crystallography. Most significantly, the crystal structure was obtained in conditions where three nominally identical units (alpha 3 beta 3) of the catalytic headgroup (F1), were each in a different configuration due to differential binding of adenine nucleotides, which at once pointed towards a rotary mechanism of ATP synthesis mediated by the asymmetry of the structure imposed by the rotating central stalk. Since this work, John has continued to unravel the secrets of this all-important enzyme for virtually all forms of life, including the structure of its membrane part (from yeast mitochondria), which demonstrated an unforeseen subunit stoichiometry that has led to new theories of the molecular mechanics of this intriguing nanomachine, the structure of the peripheral stalk or stator and the structure of the regulatory protein IF1 bound to the catalytic domain. Apart from these achievements, John has established the subunit composition of complex I, another highly complex membrane-bound enzyme of the mitochondrion, as well as identifying the functions of substrate transporter molecules in that membrane. In 1995 he was elected Fellow of the Royal Society. In 1997, he was awarded the Nobel Prize in Chemistry jointly with Dr Paul Boyer for their elucidation of the enzymatic mechanism underlying the synthesis of adenosine triphosphate (ATP). In 1999 he received his knighthood for his services to medical research from HRH The Prince of Wales. John's many other honours include the A.T. Clay Gold Medal in 1959, the Johnson Foundation Prize (University of Pennsylvania) in 1994, the CIBA medal and prize of the British Biochemical Society and the Peter Mitchell medal of the European Bioenergetics Conference, in 1996. He is a Foreign Member of L'Accademia Nazionale dei Lincei, Rome, Italy and the Royal Netherland Academy of Sciences, and a Foreign Associate of the National Academy of Sciences, USA.

The NIH Director's Wednesday Afternoon Lecture Series includes weekly scientific talks by some of the top researchers in the biomedical sciences worldwide.
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NLM Title: Energy conversion in biology [electronic resource] / John E. Walker.
Series: NIH director's Wednesday afternoon lecture series
Author: Walker, John E.
National Institutes of Health (U.S.)
Publisher:
Other Title(s): NIH director's Wednesday afternoon lecture series
Abstract: (CIT): Special 1:00 PM Director's Wednesday Afternoon Lecture Modern oxygen evolving photosynthesis requires more than 200 proteins. Many of them are organised in highly complex structures in the chloroplasts of green plants (and also in cyanobacteria) where incident light energy from the sun is entrapped in the carbohydrates and fats that provide our food with calorific value. We release the energy by respiration (controlled burning), consuming in the process most of the oxygen that we have breathed in. Of the 1000 or so proteins that are involved, about 100 of them are organised into the respiratory enzyme complexes in mitochondria that function as molecular machines to convert the redox energy derived from food-stuffs into adenosine triphosphate (ATP), the energy currency of biology. The final synthetic step is achieved by a remarkable molecular machine that has a mechanical rotary action. Its closest man-made analogue is the Wankel rotary engine. Its workings will be described and how such complex machines evolve will be discussed. Professor John Walker FRS is Director of the Medical Research Council Dunn Human Nutrition Unit in Cambridge, UK, since 1998. In 1974 he was recruited by Fred Sanger to the Laboratory of Molecular Biology in Cambridge, UK, and early on he helped to uncover details of the modified genetic code of mitochondrial DNA. In 1978 he began studying the ATP synthase from mitochondria and from bacteria, resulting in a complete sequence analysis of this complex enzyme from several species. This was the ouverture to his work leading, in 1994, to the resolution of the 3D structure of the headpiece and stalk of this remarkable energy transducer by X-ray crystallography. Most significantly, the crystal structure was obtained in conditions where three nominally identical units (alpha 3 beta 3) of the catalytic headgroup (F1), were each in a different configuration due to differential binding of adenine nucleotides, which at once pointed towards a rotary mechanism of ATP synthesis mediated by the asymmetry of the structure imposed by the rotating central stalk. Since this work, John has continued to unravel the secrets of this all-important enzyme for virtually all forms of life, including the structure of its membrane part (from yeast mitochondria), which demonstrated an unforeseen subunit stoichiometry that has led to new theories of the molecular mechanics of this intriguing nanomachine, the structure of the peripheral stalk or stator and the structure of the regulatory protein IF1 bound to the catalytic domain. Apart from these achievements, John has established the subunit composition of complex I, another highly complex membrane-bound enzyme of the mitochondrion, as well as identifying the functions of substrate transporter molecules in that membrane. In 1995 he was elected Fellow of the Royal Society. In 1997, he was awarded the Nobel Prize in Chemistry jointly with Dr Paul Boyer for their elucidation of the enzymatic mechanism underlying the synthesis of adenosine triphosphate (ATP). In 1999 he received his knighthood for his services to medical research from HRH The Prince of Wales. John's many other honours include the A.T. Clay Gold Medal in 1959, the Johnson Foundation Prize (University of Pennsylvania) in 1994, the CIBA medal and prize of the British Biochemical Society and the Peter Mitchell medal of the European Bioenergetics Conference, in 1996. He is a Foreign Member of L'Accademia Nazionale dei Lincei, Rome, Italy and the Royal Netherland Academy of Sciences, and a Foreign Associate of the National Academy of Sciences, USA. The NIH Director's Wednesday Afternoon Lecture Series includes weekly scientific talks by some of the top researchers in the biomedical sciences worldwide.
Subjects: Adenosine Triphosphate--metabolism
Energy Metabolism
Energy Transfer
Publication Types: Lectures
Webcasts
Download: To download this event, select one of the available bitrates:
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NLM Classification: QU 125
NLM ID: 101308567
CIT Live ID: 5883
Permanent link: http://videocast.nih.gov/launch.asp?13793

 

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