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Code:
FOD
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Time Slot/Poster Number:
09:00 - 9:30 am
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Session:
Biomolecules & Living Systems II
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Raman (And Ir) Studies Of Protein Structure And Dynamics
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| Hua Deng; Robert Callender
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Albert Einstein College of Medicine, Bronx, NY
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| View Abstract PDF |
| Summary |
Vibrational spectroscopy is especially useful in the study of molecular mechanism of enzymes; bond distortions as small as 0.01-0.001 Å can be discerned by vibrational spectroscopy. It is at this level of atomic resolution that enzyme induced bond distortions usually manifest themselves. Vibrational spectroscopy can follow kinetic events on the sub-picosecond time scale. For many problems involving structure/dynamics/function of proteins, such high resolutions, both spatial and time, are crucial. We discuss some of our recent studies of the vibrational structure of enzymes as well as dynamical studies involving approaches having nanosecond time resolution, relating such findings to mechanism.
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Code:
FOD
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Time Slot/Poster Number:
09:30 - 10:00 am
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Session:
Biomolecules & Living Systems II
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Comparative Studies of Human Indoleamine 2,3-dioxygenase and Tryptophan Dioxygenase
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| Syun-Ru Yeh1; Ariel Lewis-Ballester1; Dipanwita Batabyal1; Changyuan Lu1; Tsuyoshi Egawa1; Yu Lin1; Marcelo Marti2; Luciana Capece2; Dario Estrin2
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1Albert Einstein College of Medicine, Bronx, NY; 2Universidad de Buenos Aires, Buenos Aires, Argentina
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| View Abstract PDF |
| Summary |
In contrast to the wide spectrum of cytochrome P450 monooxygenases, there are only two heme-based dioxygenases in humans, tryptophan dioxygenase (hTDO) and indoleamine 2,3-dioxygenase (hIDO). hTDO and hIDO catalyze the same oxidative ring cleavage reaction of L-tryptophan (L-Trp) to N-formyl kynurenine (NFK), the initial and rate-limiting step of the kynurenine pathway. Despite immense interest, the mechanism by which the two enzymes execute the dioxygenase reaction remains elusive. Here we present comparative studies of the two important classes of heme-based dioxygenases by using resonance Raman spectroscopy, combined with QM/MM simulations.
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Code:
FOD
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Time Slot/Poster Number:
10:00 - 10:20 am
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Session:
Biomolecules & Living Systems II
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Resonance Raman Characterization Of The Flavin Radical In Cryptochrome DASH
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| Johannes Schelvis1; Carlos Lucero1; Azaria Eisenberg2; Yvonne Gindt3
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1Montclair State University, Montclair, NJ; 2New York University, New York, NY; 3Lafayette College, Easton, PA
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| View Abstract PDF |
| Summary |
Cryptochrome DASH is a blue-light photoreceptor that belongs to the photolyase/cryptochrome family. Photolyase repairs cyclobutane pyrimidine dimers on DNA, and cryptochrome DASH is the only cryptochrome that has DNA-repair capability, albeit only for single-stranded DNA. In this paper, the differences and similarities of the flavin adenine dinucleotide radical in photolyase and cryptochrome DASH as well as the effect of substrate binding are investigated with resonance Raman spectroscopy. Isotopically-labeled N5-methyl riboflavin radical is used to facilitate the interpretation of the Raman spectra. This new information is discussed in light of differences in structure and physicochemical properties between the two enzymes.
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Code:
FOD
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Time Slot/Poster Number:
10:20 - 10:40 am
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Session:
Biomolecules & Living Systems II
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Structure-Function Relationships in Spider Silk
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| Michel Pézolet; Thierry Lefèvre; Marie-Eve Rousseau; Simon Boudreault; Conrad Cloutier
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Université Laval, Quebec City, Canada
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| View Abstract PDF |
| Summary |
The different types of silk produced by orb-weaving spiders display various mechanical properties to fulfill diverse functions. Since Raman spectromicroscopy is a unique technique allowing the study of small silk, we have used this technique to characterize the structure of proteins of silk fibers harvested from the web, cocoon and prey wrapping of spiders. In addition, to better understand the molecular events occurring during the spinning process, we have also studied the conformation of the proteins in the silk glands. The results show an interesting diversity of the initial and final secondary structure of the spidroins of spiders.
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