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RESEARCH PRODUCT

24. Molecular Biology

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Publisher Summary This chapter discusses the use of neutron scattering in molecular biology. The neutron small-angle camera D11 is discussed. The objective of scattering studies on biological macromolecules is to determine molecular conformations and arrangements, particularly those that may contribute to specific biological functions. The principles of neutron scattering are very similar to those of x rays, but some important differences exist due to the different characteristics of the two radiations. If the scattering specimen is a single macromolecule with no regular separation between neighboring structures, then the scattering is continuous. In a coherent scattering process, the amplitude of the wave scattered by each atom, specified by modulus and phase, adds to the total amplitude of the macromolecule. The process of protein biosynthesis involves major structural changes of the active sites of the ribosome. Reading the message of the codon, ordering the desired amino acid, checking and binding the amino acid to the nascent peptide in a three-stage process of the transfer RNA (tRNA), and secretion of the peptide chain are just some steps that necessitate movements or conformational changes of the constituents of the ribosome.