Residual space

Amino acids per turn Each turn of an a-helix contains 3.6 amino acids. Thus, amino acid residues spaced three or four apart in the primary sequence are spatially close together when folded in the a-helix. 

The existence of electrostatic interactions between oppositely charged residues and hydrogen bonding between side chains agrees with the observations in protein helices that (1) helix probability correlates with the frequency of occurrence of oppositely charged residues spaced i, i + 4 apart in proteins 88 and (2) there is a strong tendency for nearby, oppositely charged, side chains to point toward each other. 89 In the case of C-peptide, the side-chain interactions were also evident in the crystal structure of RNase A. 

Cys residues spaced i, i + 3 apart have been covalently linked to obtain cyclic peptides which fold into a 310-helix. Balaram et al.[159l synthesized Boc-c[-Cys-Pro-Aib-Cys-]-NHMe, wherein a disulfide bond links the two Cys residues. Pro and Aib residues were used to restrict conformational flexibility. NMR and X-ray diffraction studies revealed a highly folded, compact formation of an incipient 3i0-helix, with the S—S bridge lying approximately parallel to the helix axis. 

Fig. 18. Helical net diagrams (A) and amino acid sequences (B) of c i, ala, and an,. In the helical nets the hydrophobic residues are circled, and potential salt bridges between the side chains of residues spaced at positions i 3 or residues at / 4 are indicated by solid and dashed lines, respectively.

Recent research activities on nanoporous materials have stimulated fundamental studies on adsorption mechanism in micropores [1 5]. Both of the precise measurement of high resolution adsorption isotherms from the low P/Po region and molecular simulation showed the presence of monolayer adsorption on the micropore walls and further filling in the residual spaces after monolayer completion for supermicropores (0.7 nm < pore width w <2 nm) the contribution by the monolayer to the filling in the residual spaces is comparable to that by the pore walls [6-10]. Systematic researches on activated carbon fiber (ACF) having slit-shaped micropores[l 1,12] have contributed to elucidation of the mechanism of micropore filling to develop better adsorbents in adsorption and separation engineering. 

Kelch and WD repeats consist of repeated sequence motifs with hallmark residues spaced at regular intervals (Fig. 1). In each case, only a handful of residues arc consistently conserved (bold residues in Fig. 1 sequence alignments) and even these positions can tolerate substitutions, making the identification of all repeats by sequence scanning algorithms alone difficult. In a number of cases, additional repeats present in a protein were only recognized after structural determination (Table 1). 

The second approach makes use of the contribution to residual space. Process upsets and changes in sensor characteristics can be identified by analyzing the residual space. To investigate variables being affected by such disturbances, the contribution of each variable that ultimately triggers the SPE limit should be calculated as follows ... 

The electrode system connecting the cluster to the outer world must be fabricated by lithographic techniques self-assembly of the clusters into the residual space-gap makes the step down to the molecular scale. Because the properties of the central electrode are adjustable chemically this arrangement could be suitable for the utili-... 

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