N-terminal segment preference for TATA box


Implicit in the presumption of folding pathways is the existence of intermediate, partially folded conformational states. The notion of intermediate states on the pathway to a tertiary structure raises the possibility that segments of a protein might independently adopt local and well-defined secondary structures (a-helices and /3-sheets). The tendency of a peptide segment to prefer a particular secondary structure depends in turn on its amino acid composition and sequence.  [c.197]

These concepts play an important role in the Hard and Soft Acid and Base (HSAB) principle, which states that hard acids prefer to react with hard bases, and vice versa. By means of Koopmann s theorem (Section 3.4) the hardness is related to the HOMO-LUMO energy difference, i.e. a small gap indicates a soft molecule. From second-order perturbation theory it also follows that a small gap between occupied and unoccupied orbitals will give a large contribution to the polarizability (Section 10.6), i.e. softness is a measure of how easily the electron density can be distorted by external fields, for example those generated by another molecule. In terms of the perturbation equation (15.1), a hard-hard interaction is primarily charge controlled, while a soft-soft interaction is orbital controlled. Both FMO and HSAB theories may be considered as being limiting cases of chemical reactivity described by the Fukui ftinction.  [c.353]

Two concepts entangling mass and velocity made chaos in eighteenth-century dynamics, Newton s vis niotrix mv and Leibniz s vis viva mtf (now written A m-v, as first proposed by Gaspard Coriolis in 1829). It was a battle ofeoncepts but also a battle of terms. Then casually in 1807 Thomas Young in his Course of Lectures on Natural Philosophy and the Mechanical Arts, dropped this remark The term energy may be applied -with great propriety to the product of the mass or weight of a body times the number expressing the square of its velocity. Proper or not, energy might have fallen still born in science had not John Farey also, with due praise of Young, twice used it in 1827 in his History of the Steam Engine for vis viva. There, dormant, the word lay, four uses in two books, until 1849, when Thomson in last-minute doubt added this footnote to his second paper on Carnot s theorem, An Account of Carnot s Theory on the Motive Power of Heat When thermal agency is spent in conducting heat through a solid what becomes of the mechanical effect it might produce Nothing can be lost in the operation of nature—no energy can be destroyed. What then is produced in place of the mechanical effect that is lost  [c.1033]


See pages that mention the term N-terminal segment preference for TATA box : [c.400]    [c.190]    [c.263]    [c.203]    [c.457]   
Introduction to protein structure (1999) -- [ c.7 , c.158 ]