Nature uses vitamin B12 and its derivatives to perform fascinating chemical reactions that are essential for life. Enzymes that harness the reactivity of vitamin B12 are known for having dynamic transitions that move the co- factor between multiple sites in the protein. One such enzyme is the complex formed by the corrinoid iron-sul- fur protein and its methyltransferase (CFeSP/MeTr) from a microbial carbon ?xation pathway that is responsi- ble for producing an astounding 1012 kg of acetate annually. Microbes that utilize this pathway can be found in many contexts, including the human gut. Furthermore, a B12-dependent methyl transfer reaction is performed by the homologous enzyme methionine synthase (MetH) in humans to produce methionine from homocysteine. Prior studies of CFeSp/MeTr using X-ray crystallography suggest that large domain motions are an essential component of the enzyme turnover mechanism. Remarkably, enzyme turnover has been shown to occur within the crystal, and the motion of the B12 domain is the largest known for any protein in the crystalline state. We propose to develop new experimental and theoretical methods for X-ray scattering from MetH in solution and diffuse scattering from CFeSP/MeTr crystals to understand how long-ranged correlated motions in B12-depen- dent metalloenzymes regulate catalytic activity.

Public Health Relevance

Vitamin B12 is an essential nutrient for humans as well as bacteria that are important for environmental and human health. Enzymes that use B12 are often ??oppy?. Understanding how they choreograph their motions is essential for understanding their functions.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Postdoctoral Individual National Research Service Award (F32)
Project #
1F32GM117757-01A1
Application #
9192141
Study Section
Special Emphasis Panel (ZRG1)
Program Officer
Barski, Oleg
Project Start
2016-09-26
Project End
2018-09-25
Budget Start
2016-09-26
Budget End
2017-09-25
Support Year
1
Fiscal Year
2016
Total Cost
Indirect Cost
Name
Princeton University
Department
Chemistry
Type
Schools of Arts and Sciences
DUNS #
002484665
City
Princeton
State
NJ
Country
United States
Zip Code
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Meisburger, Steve P; Ando, Nozomi (2017) Correlated Motions from Crystallography beyond Diffraction. Acc Chem Res 50:580-583
Meisburger, Steve P; Thomas, William C; Watkins, Maxwell B et al. (2017) X-ray Scattering Studies of Protein Structural Dynamics. Chem Rev 117:7615-7672