Protein hydrogenation

The secondary structure of a protein is determined by hydrogen bonding between CDO and N—H groups of the peptide linkages that make up the backbone of the protein. Hydrogen bonds can exist within the same protein... 

Figure 13.1 Secondary structure of proteins hydrogen bonding in 3-sheets ...

Hydrogen bonds. Hydrogen bonds (see See-tion 13.3) are responsible for ihe fnndamenlal characterislics of the a-helix and P-pleated sheet in addition, they contribnte to the final shape of a globnlar protein. Hydrogen bonds can form... 

Therefore, those hydrogen atoms that are present in stable H-bonds will resist exchange with the solvent. H-bonds lying on the surface of many proteins readily undergo exchange. In addition to deuterium, one can also use tritium-labeled water to follow the kinetics of protein hydrogen exchange. 

Deuterium-hydrogen exchange in proteins, HYDROGEN EXCHANGE IN PROTEINS DEVIATION DEWAR STRUCTURES DFP,... 

The main molecular interactions involved in phenol-protein interactions are arbitrarily represented in Figure 9.2. A real case of flavonoid-protein hydrogen bond network is depicted in Figure 9.3. It refers to one of the rare examples of a flavonoid-protein complex... 

Protein structure is stabilized by multiple weak interactions. Hydrophobic interactions are the major contributors to stabilizing the globular form of most soluble proteins hydrogen bonds and ionic interactions are optimized in the specific structures that are thermodynamically most stable. 

Certain CYPs undergo mechanism-based inactivation as a result of conversion of their prosthetic heme groups to products that irreversibly bind to the protein. Hydrogen peroxide and cumene hydroperoxide partially degrade the prosthetic heme to monopyrrole and dipyrrole fragments that bind to the protein (24). Presently, no drugs have been shown to fall into this class. 

In polypeptides and proteins, hydrogen bonds are of polar origin and are usually stronger than other noncovalent bonds. Both backbone amides and... 

H. Qian, S. L. Mayo, and A. Morton. Protein hydrogen exchange in denaturant quantitative analysis a two-process model. Biochemistry, 33 8167-8171, 1994. 

In future high-resolution crystal structure studies of proteins, hydrogen bonding has to be analyzed in terms of two-center and three-center interactions. It should be stressed that three-center bonds may be especially important in protein dynamics because they can be regarded as transition intermediate from one two-center bond to another (see Part IV, Chap. 25). 

Protein hydrogen atoms bound to N, O, or S are in constant exchange with solvent protons, and therefore they can be exchanged readily by deuterium. The exchange reaction can be followed by measuring a series of correlation spectra... 

Ishima R, et al. Carbonyl carbon transverse relaxation dispersion measurements and ms-micros timescale motion in a protein hydrogen bond network. J. Biomol. NMR 2004 29 187-198. Ishima R, Torchia DA. Extending the range of amide proton relaxation dispersion experiments in proteins using a constant-time relaxation-compensated CPMG approach. J. Biomol. NMR 2003 25 243-248. 

---