Modified crystallographic studies

A crystallographic study of drug binding to HSA provides a valuable resource for structure-based design efforts to modify protein binding affinity of... 

The Di Xia research group has completed X-ray crystallographic studies of cytochrome bci with a number of different inhibitors (PDB ISQB, ISQP, ISQQ, ISQV, ISQX). Crystals suitable for crystallography were obtained by co-crystallization of the inhibitor with the native enzyme. Data for two of the inhibitor-modified cytochrome bci complex (PDB ISQP and ISQX) are included in Table 7.6 and Table 7.7. Qne inhibitor-enzyme complex studied by... 

Jarrahpour et al. [135] have described the synthesis of novel mono- and bis-spiro-[S-lactams 231 and 233, respectively, from benzylisatin 229 (Scheme 52). The starting substrate, benzylisatin 229 was prepared by reaction of isatin 228 with benzyl bromide and calcium chloride in DMF. The benzylisatin substituted imines 230 and di-imines 232 were further subjected to Staudinger reaction with ketenes derived from methoxy, phenoxy, and phthaloglycyl chlorides to afford novel mono- and bis-spiro-p-lactams 231 and 233, respectively. The configuration of benzylisatin 229 and monocyclic spiro-p-lactams 231 was established by X-ray crystallographic studies. These spiro-p-lactams will be studied as precursors of modified p-amino acids, (3-peptides and monobactam analogues. 

A very good example is the study of the extent to which residues of the loop polypeptide of lysozyme contributes to specificity. The loop peptide comprises residues 64-80 in which Cys-64 and Cys-80 form a disulfide bond, and thus this structure is highly conformational because opening the disulfide bond destroyed immunological activity. From the X-ray crystallographic study (Fig. 13), the loop peptide occurs in an exposed position. Figure 14 shows the sequence of the synthetic loop peptide and the capacity of synthetic loop peptides containing residues modified... 

A systematic view on the topic of complexation and complexes in the literature shows a great number of important research results. This expanding field covers studies of various systems, including antibody-antigen complexes, proteinase-inhibitor complexes, lipid-based delivery vehicles, metal complexes with DNA base pair, and aqua ligand in the coordination sphere of metal, The metal-modified structures are dominated by these metal-base interactions. However, the structural role of the water molecules in the complexes is quite apparent, as suggested by crystallographic studies.f ... 

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