Conformations and biological activity

Conformational analysis has been used to find and predict conformations which maximize antibiotic activity, using x-ray crystal stmctures coupled with nmr and cd spectra. An early approach utilized the Dale diamond lattice conformational model (480), which was extended to other diamond lattice models (472,481—483). Other studies have reHed on nmr data (225,484—491). However, extensive correlations between conformation and biological activity have not been successful (486,492). 

Kessler, H. Peptide conformations. 19. Conformation and biological activity of cyclic peptides. Angew. Chem. Int. Ed. 

L. Lakiewicz D. B. Sherman A. E. Spatola, Subtle Amide Bond Surrogates The Effect of Backbone Thioamides on the Physical Properties, Conformation, and Biological Activities of Peptides. In Peptides J. E. Rivier, R. G. Marshall, Eds. ESCOM Leiden, 1990 p 976. 

In addition to antibodies, numerous human blood glycoproteins have been produced in transgeiuc plants. Most are indistinguishable from their mammalian counterparts in terms of amino acid sequence, conformation, and biological activity. However, structural differences can be observed with... 

Fig. 5.8 Correlation between supramolecular structure/conformation and biological activity for various forms of lipid A at 37 °C.

Peptides and proteins have individual and unique amino acid sequences (residues), giving them unique structural conformations and biological activity. 

Operating conditions with SC CO2 are considered benign, especially for processing macromolecules such as peptides, proteins, and nucleic acids. The conventional method of protein production lyophilization subjects macromolecules to freeze-thaw cycles, potentially affecting solution conformation and biological activity. " ... 

It is of interest to point out that native conformation and biological activity of some enzymes and antibodies is recoverable after denaturation under conditions such as were used in the investigation of Tanford et al. This clearly supports the widely held assumption that the amino acid sequence of a protein is the sole determinant of its three dimensional native structure in water, a conformationally "ideal solvent for all biological polymers. 

Bovy, P. R., Getman, D. P., Matsoukas, J. M. and Moore, G. J. (1991) Influence of polyfluori-nation of the phenylalanine ring of Angiotensin-II on conformation and biological-activity. Biochimica et Biophysica Acta, 1079(1), 23-28. 

ASSUMPTIONS IN 3D-QSAR. THE BIOACTIVE CONFORMATION AND BIOLOGICAL ACTIVITY... 

Ballio, A., S. Castellano, S. Cerrini, A. Evidente, G. Ran-DAzzo, and A. L. Segre, H-NMR conformational study of fiisi-coccin and related compounds Molecular conformation and biological activity. Phytochemistry, 30, 1137-146 (1991). 

Progress in any field requires information on the state of well-defined systems as a function of conditions. Advancement is thus intimately linked to the availability of experimental probes capable of providing accurate and detailed information. Important metrics of biomolecules at interfaces include the interfacial composition distributions in molecular orientation, molecular spatial arrangement, and intramolecular conformation and biological activity. In this section, several experimental techniques probing the physical properties of biomolecules at interfaces are introduced these are grouped into optical, piezoelectric, and scanning probe methods. Further details can be found in other excellent reviews (62,188,189). 

TTie death of a human being below a blood pH of 7.0 and above a pH of 7.9 is enough testimony for the importance of pH to life in general. Examples may also be cited of death of tissue cultures and bacterial cultures in inadequately buffered m ia. It is therefore a veiy obvious conclusion that biomolecujes are profoundly affected by changes in pH. In any case, most of the important conponents of the living cell are acidic, basic, or amphoteric and any alteration in the pH of the environment profoundly affects their state of ionization and thereby their conformation and biological activity. 

Relationship between Nucleoside Conformation and Biological Activity... 

Dorman, D , and Bovey, F.A. (1973) Carbon-13 Magnetic Resonance Spectroscopy, The Spectrum of Proline in Oligopeptides, J. Org. Chem., 38, 2379-2383. Kessler, H. (1982) Conformation and Biological Activity of Cyclic Peptides, Angew. Chem., Int. Ed. Engl., 21, 512-523. 

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