High-resolution X-ray analysis

High resolution X-ray analysis of protein structures shows that the conformational categories of the connecting peptides which link the a-helices and -sheets are limited. Such well defined types of folding units, such as aa- and PP-hairpins, and aP- and Pa-arches, are referred to as supersecondary structures. One important step towards building a tertiary structure from secondary structures is to identify these supersecondary structure... 

In fact, there are many reported differences between a-lactalbumin and lysozyme in solution, in comparison with the similarity between these proteins indicated by high-resolution X-ray analysis of their crystals. 

Examplary for the G-protein-coupled receptors, Fig. 5.6 shows the two dimensional model of bovine rhodopsin. The three-dimensional structure of rhodospsin has been directly visualized high resolution X-ray analysis (Palczewski et al., 2000 see Fig 5.3)... 

NPY is a member of the pancreatic polypeptide (PP) family of peptide hormones (Glover et al., 1985 Schwartz et al., 1990). A high-resolution X-ray analysis of one member of this family, avian pancreatic polypeptide (aPP), has been reported (Blundell et al., 1981 Glover et al., 1983), and a tertiary structure, referred to as the PP-fold (or the hair-pin loop), for the PP family was proposed. The PP-fold consists of... 

Results from an early unrefined met myoglobin neutron analysis ( ) based on the x ray structure by Watson and Kendrew ( ) showed a total of 106 water peaks. In that analysis, only peaks that had a peak height equivalent to one-half D2O molecule were considered. More recently, Takano (O, in a refined high resolution x-ray analysis of met myoglobin, found 72 water molecules, and in the present refined neutron analysis of CO-Mb, only AO water molecules were found. These water molecules were identified in a difference map where the features depicting the protein had been subtracted. The protein structure itself had been refined by successive real-space refinement of eight... 

High-Resolution X-Ray Analysis of Drug-Quadruplex Interactions... 

Note added in proof recent high resolution X-ray analysis of iron derivatives of EcFtna crystals show that Gla 130 ligates both side B and site C Fe atoms forming a bridge between them rather than alternating as a ligand of either site as described on p 231 and depicted in Fig. 15-4. 

For the first time, it was possible in 2003 to determine the structure of human testicular ACE by means of high-resolution X-ray analysis (Fig. 5.17). [18, 19] There are two isoforms of ACE the somatic form, a glycoprotein with a chain of 1,277 amino acids, and the ACE of germ cells this is smaller and comprises 701 amino acids. The somatic ACE contains two homologous domains, the N- and C-domains, the latter of which being identical with the testicular ACE. This domain is responsible for the regulation of blood pressure. 

Northrop had described the first crystalline preparation derived from trypsin-treated antibody in 1942 (Northrop, 1942), and a number of investigators subsequently reported crystalline antibodies or antibody fragments (Nisonoff et a/., 1967 Hochman et al., 1973). The first Fab fragment crystals, however, which had potential for high-resolution X-ray analysis became available only in the late 1960s. A human IgGl myeloma protein, NEW, was analyzed at 2 A resolution by Roberto Poljak and his collaborators at Johns Hopkins Medical School (Poljak et aL, 1974), and a mouse IgA myeloma protein, derived from the McPC 603 tumor, was... 

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