High-resolution crystal structure

Binda C, Li M, Hubalek E, Restelli N, Edmondson DE, Mattevi A. Insights into the mode of inhibition of human mitochondrial monoamine oxidase B from high-resolution crystal structures. Proc Natl Acad Sci USA 2003 100 9750-5. 

The pH dependence of the rate of modification shows that the pKa of Asp-32 is less than 3.165 It is seen in the high-resolution crystal structures that the carboxyl groups of the two aspartate residues are hydrogen-bonded to each other. This is similar to the ionization of maleic acid, which has pKa values of 1.9 and 6.2 (equation 16.30). 

Ileperuma NR, Marshall SDG, Squire CJ, Baker HM, Oakeshott JG, Russell RJ, Plummer KM, Newcomb RD, Baker EN (2007) High-resolution crystal structure of plant carboxyesterase AeCXEl, from Actinidia eriantha, and its complex with a high-affinity inhibitor paraoxon. Biochemistry 46 1851-1859... 

MacGillivray, R.T., Moore, S.A., Chen, J., Anderson, B.F., Baker, H., Luo, Y., Bewley, M., Smith, C.A., Murphy, M.E., Wang, Y., Mason, A.B., Woodworth, R.C., Brayer, G.D. and Baker, E.N. (1998) Two high-resolution crystal structures of the recombinant N-lobe of human transferrin reveal a structural change implicated in iron release, Biochemistry, 37, 7919-7928. 

The high-resolution crystal structure of MPT synthase [35, 36] revealed that the enzyme forms an elongated, heterotetrameric molecule (Figure 3.3A) with overall dimensions of 93 X 28 X 27 A. The small (MoaD) subunits are positioned on oppo-... 

Whether the structural similarity of the two complexes is connected with similar functions remains unclear. The exact arrangement of CSN and lid subunits within their complexes remains uncertain in the absence of high-resolution crystal structures for the two complexes. 

Despite considerable biochemical work, high-resolution crystal structure determination of native RNase A and S, and some medium-resolution studies of RNase A-inhibitor complexes, a number of questions existed concerning the details of the catalytic mechanism and the role of specific amino acids. Study of the low-temperature kinetics and three-dimensional structures of the significant steps of the ribonuclease reaction was designed to address the following questions. 

The ribosome is a unique cellular machine in that its main functional component is RNA whereas proteins seem to play only a structural role. For a long time, it has been debated whether RNA or proteins contribute most to the ribosome s function. With the determination of high-resolution crystal structures, this question could finally be answered. Clearly, these structures have revolutionized the field of ribosome studies. Already in the 1980s, Yonath and coworkers had grown crystals of active ribosomes that diffracted to about 0.6 nm (6 A) (1 A = 0.1nm) resolution. However, owing to the large size of the ribosome of about 2 500 000 Da (lDa=lgmoP), the ribosome structure was not solved to atomic resolution until tbe year 2000. 

Saeo, M.K., Moure, C.M., Burnett, J.C., Joshi, G.S., and Abraham, D.J. High-resolution crystal structure of deoxy hemoglobin complexed with a potent allosteric effector. Protein Sci. 2001, 10, 951-957. 

High-resolution crystal structures are known for both the diheme enzymes to be discussed in this article. We describe these structures and relate them to the mechanisms of the two enzymes before trying to compare the common features of these two types of enzyme. For example, they are both able to interact, at least in vitro, with c-type cytochromes... 

Divne, C., Stahlberg, J., Teeri, T. and Jones, T. (1998) High-resolution crystal structures reveal how a cellulose chain is bound in the 50 Angstrom long tuimel of cellobiohydrolase I from Trichoderma reesei. J. Mol. Biol., 275, 309-325. 

D. Dohritzsch, S. Konig, G. Schneider, G. Lu, High resolution crystal structure of pyruvate decarboxylase from Zymomonas mohilis. Implications for substrate activation in pyruvate decarboxylases. J. Biol. Chem. 1998, 273, 20 196-20 204. 

Based on high resolution crystal structures, detailed understanding of the molecular principles of allosteric regulation for several enzyme systems could be gleamed. One of the best studied examples is that of phosphofructokinase from Bac. stearothermophilus (Schirmer and Evans, 1990). 

Two different enzymatically active forms of PFK could be identified which may be considered the R and T form in the framework of the symmetry model. The R form possesses a high affinity for the substrate fructose-6-P, the T form binds fructose-6-P with lower affinity. Upon binding of the inhibitor phosphoenolpyruvate, PFK converts to the T form. The enzyme is foimd in the R form upon binding the substrates (ATP or fructose-6-P) or the activator (ADP). There exist high resolution crystal structures of both forms. 

In the high resolution crystal structure of the GTP form of Ras protein, a tightly bound water molecule is visible located in an optimal position for nucleophilic attack on the y-phosphate (Wittinghofer et al., 1993). The water molecule is fixed in a defined position by H-bridges with GIn61 and Hir35. As described in 5.4.4 for the a-subunits of the heterotrimeric G-proteins, GTP hydrolysis takes place by an in-line attack of the nucleophilic water molecule on the y-phosphate, for which a pentagonal, bipyramidal transition state is postulated. 

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