High-resolution X-ray crystal structures

Bode, W., Papamokos, E., Musil, D. The high-resolution X-ray crystal structure of the complex formed between subtilisin Carlsberg and eglin c, an elastase inhibitor from the leech Hirudo medicinalis. Eur. J. Biochem. 166 (1987) 673-692... 

Calcium-Binding Characteristics of Sites in Moderate- to High-Resolution X-Ray Crystal Structured... 

The NADP-IDH from Escherichia coli has been thoroughly studied. It is a dimeric protein of two identical 40-kDa subunits. High-resolution X-ray crystal structures have been determined for the enzyme with and without substrate [16,17], and for the pseudo-Michaelis complex of the enzyme with isocitrate and NADP [18], Structures of sequential intermediates formed during the catalytic action of IDH are also available [19], Additionally, the kinetic and catalytic mechanisms have been determined in detail [20], Amino acid residues which are involved in interactions with substrate, coenzyme, metal ions, and catalysis have been identified [10,21],... 

The introduction and implementation of heteronuclear-based multidimensional techniques have revolutionized the protein NMR field. Large proteins (> 100 residues) are now amenable to detailed NMR studies and structure determination. These techniques, however, necessarily require a scheme by which and isotopes can be incorporated into the protein to yield a uniformly labeled sample. Additional complications, such as extensive covalent post-translational modifications, can seriously limit the ability to efficiently and cost effectively express a protein in isotope enriched media - the c-type cytochromes are an example of such a limitation. In the absence of an effective labeling protocol, one must therefore rely on more traditional proton homonuclear NMR methods. These include two-dimensional (1) and, more recently, three-dimensional H experiments (2,3). Cytochrome c has become a paradigm for protein folding and electron transfer studies because of its stability, solubility and ease of preparation. As a result, several high-resolution X-ray crystal structure models for c-type cytochromes, in both redox states, have emerged. Although only subtle structural differences between redox states have been observed in these... 

IDH displays a 7000-fold preference for NADP whereas IMDH displays a 100-fold preference for NAD (5-7). High resolution X-ray crystal structures have been obtained for both enzymes with and without coenzymes bound (3, 4, 8, 9). The kinetic and catalytic mechanisms have also been determined (5, 7). In addition, a large quantities of recombinant proteins are readily purified, facilitating biochemical and structural analyses. The strict specificity together with an extensive knowledge of their structure and biochemistry makes IDH and IMDH ideal targets for rationally engineering coenzyme specificity. 

Thrombin inhibition is a fruitful source of raw data for the study of molecular recognition. Several groups have determined, published, and deposited coordinates for sets of high-resolution X-ray crystal structures. In combination with binding and kinetic data, it is now possible to map the thrombin active site in some detail in terms of both structural changes and the energies of interactions. 

A listing of the X-ray crystal structure (arranged in chronological order) of plant lectins is presented in Table 2 commencing with the structure of concanavalin A at 3 A resolution [38,39]. Interestingly, it was not until 1989 that a definitive high resolution X-ray crystal structure of the concanavalin A-methyl a-D-mannopyranoside complex was elucidated [40], and the most recently reported is that of peanut agglutinin [41]. Reviews on carbohydrate-protein interactions are also worthy of note [42-45]. 

High-resolution X-ray crystal structures have been reported for the GPATases present in E. and... 

The active site geometries (Figure 2.14) of the sulfite oxidizing enzymes are quite similar and examples of high-resolution X-ray crystal structures can be found for the S. novella sulfite dehydrogenase (bacterial)/ A. thaliana sulfite oxidase (plant)/ bacterial YedY/ and vertebrate sulfite oxidase. ... 

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