Structural similarities and

Figure 1 The basis of comparative protein structure modeling. Comparative modeling is possible because evolution resulted in families of proteins, such as the flavodoxin family, modeled here, which share both similar sequences and 3D structures. In this illustration, the 3D structure of the flavodoxin sequence from C. crispus (target) can be modeled using other structures in the same family (templates). The tree shows the sequence similarity (percent sequence identity) and structural similarity (the percentage of the atoms that superpose within 3.8 A of each other and the RMS difference between them) among the members of the family.

A number of nitrogen-fixing bacteria contain vanadium and it has been shown that in one of these, Azotobacter, there are three distinct nitrogenase systems based in turn on Mo, V and Fe, each of which has an underlying functional and structural similarity.This discovery has prompted a search for models and the brown compound [Na(thf)]+[V(N2)2(dppe)2] (dppe = Pli2PCH2CH2PPh2) has recently been prepared by reduction of VCI3 by sodium naphthalenide... 

Thus, two materials with the same solubility parameters will be soluble in one another due to the fact that their mixed enthalpy is zero. This is consistent with the fact that chemically and structurally similar materials tend to be soluble in one another. 

Peptidases have been classified by the MEROPS system since 1993 [2], which has been available viatheMEROPS database since 1996 [3]. The classification is based on sequence and structural similarities. Because peptidases are often multidomain proteins, only the domain directly involved in catalysis, and which beais the active site residues, is used in comparisons. This domain is known as the peptidase unit. Peptidases with statistically significant peptidase unit sequence similarities are included in the same family. To date 186 families of peptidase have been detected. Examples from 86 of these families are known in humans. A family is named from a letter representing the catalytic type ( A for aspartic, G for glutamic, M for metallo, C for cysteine, S for serine and T for threonine) plus a number. Examples of family names are shown in Table 1. There are 53 families of metallopeptidases (24 in human), 14 of aspartic peptidases (three of which are found in human), 62 of cysteine peptidases (19 in human), 42 of serine peptidases (17 in human), four of threonine peptidases (three in human), one of ghitamicpeptidases and nine families for which the catalytic type is unknown (one in human). It should be noted that within a family not all of the members will be peptidases. Usually non-peptidase homologues are a minority and can be easily detected because not all of the active site residues are conserved. 

Less detailed information is available concerning the rates of reactions of most hydroxy salts of inorganic acids indeed, the qualitative changes occurring during stepwise or overall removal of water have not been established for many systems. The behaviour characteristics of a number of hydroxy halides are mentioned below, as are the dehydroxylations of representative minerals. Some aspects of the relationships between the reactions of minerals and structurally similar metal hydroxides are critically discussed by Brett et al. [92]. 

Penicillin G acylase (PGA, EC 3.5.1.11, penicillin G amidase) catalyzes the hydrolysis of the phenylacetyl side chain of penicillin to give 6-aminopenicillanic acid. PGA accepts only phenylacetyl and structurally similar groups (phenoxyacetyl, 4-pyridylacetyl) in the acyl moiety of the substrates, whereas a wide range of structures are tolerated in the amine part [100]. A representative selection of amide substrates, which have been hydrolyzed in a highly selective fashion, is depicted in Figure 6.36. 

E. SLIPPER-2001 - software for predicting molecular properties on the basis of physicochemical descriptors and structural similarity. /. Chem. Inf. Comput. Sci. 2002, 42, 540-549. 

To clarify the nature and activity of these toxins, rhizome exudates (washings), compounds isolated from rhizomes (dhurrin, taxiphyllin, p-hydroxybenzaldehyde), and structurally similar compounds were tested against radish and tomato root growth and growth of nine species of bacteria. Figures 4 and 5 show the results of the radish and tomato bioassay of pure compounds. Dhurrin and toxiphyllin showed little activity in these assays, whereas j>-hydroxybenzaldehyde was active in the radish bioassay. 

Scheme 20 Lobophorolide (72) from the brown alga Lobophora variegata, and structurally similar natural products from cyanobacteria and the sponge Theonella swinhoei...

In our own preliminary studies [86] on parallel procedures under microwave-enhanced conditions, we have used the Radley s RDT 24 place PTFE carousel reaction station on the turntable of the Matsui M 169BT microwave oven. In this way, we have studied the catalytic activity of RhCl3 and Pd(OAc)2 towards the reduction or dehalo-genation of 4-bromocinnamic acid and structurally similar compounds. A nine-reaction matrix was used under microwave-enhanced conditions as illustrated in Scheme 13.9 - greatly reduced reaction times and easy optimization of reaction conditions are immediate benefits. As robotics come to play an increasingly important role in chemistry, one can immediately see more sophisticated labeling experiments being undertaken. 

Potential for diamond-bearing kimberlites is also present Sambaa K e area. There are basement and structural similarities with the Buffalo Head Hills kimberlite field, Alberta (Prior et al. 2007) and there is ongoing diamond exploration within the WCSB to the north as well. Further discussion has altered the potential boundaries for the proposed protected area on the Horn Plateau and discussions are ongoing before any permanent decisions are made by all parties involved. Analytical results for the remaining two areas are pending. 

Fig. 2.3-12. Molecular structures of 59, 60, 60a, and topological relationships of 59 and 60 to the corresponding sections from the solid-state structure of elemental aluminum, and structural similarities of the clusters Ali2R6 and In Rs- In the latter cluster the octahedral sections are highlighted.

Steven, A. C., and Maueizi, M. R. Enzymatic and structural similarities between the Escherichia coli ATP-dependent proteases, ClpXP and ClpAP. J. Biol. Chem. 1998, 273, 12476-12481. 

Hall, LH. and Kier, LB. The E-state as the basis for molecular structure space definition and structure similarity. 

Rocks that contain talc, or the chemically and structurally similar minerals mentioned previously, are usually the result of alteration and recrystallization of rock formations that contained magnesian silicate minerals. Steati-zation or serpentinization are the terms given the processes that create layered (sheet) silicates from chain or other tetrahedral arrangements adopted by silicate minerals (see Fig. 2.1). The recrystallization process is expedited by temperature and pressure, and especially through the action of hydrothermal solutions. 

Primidone is chemically and structurally similar to phenobarbital with the exception that the carbonyl group on Cj is replaced by a methylene group. This modification leads to the production of a drug with strong anticonvulsant properties without expressed soporific effects. 

Formula CaCN2 MW 80.11 cyanamide ion is linear and structurally similar to CO2 Structure N = CN = Ca Synonyms calcium carbimide lime nitrogen nitrolime... 

For centuries opium was used for both medicinal and recreational purposes. Derived from the poppy Papaver somniferum, it contains numerous opiates, the primary one of which is morphine. The term opiate has largely been replaced by opioid, which represents all compounds with morphinelike activity and includes morphine, morphine derivatives, and peptides. Opiate is used to refer to morphinelike drugs derived from the plant and structurally similar analogues. These drugs are frequently referred to as narcotics, a Greek term for stupor, which is scientifically obsolete. Even in its early history, opium presented a problem when it was smoked or taken orally. The introduction of the hypodermic needle and syringe, however, drastically enhanced the euphoric properties of opioids and thereby altered their abuse liability. In addition, the synthesis of heroin resulted in an opioid that was more potent than morphine and ideally suited for intravenous administration. 

The AAHs are functionally and structurally similar, which is reflected in a high sequence similarity (Fig. 1). Phylogenetic and functional analyses place a protozoan PAH close to the ancestor sequence of the AAHs, thus aiding to define the evolutionary history of this enzyme family (10). While bacterial PAH is monomeric, the mammalian AAHs are tetrameric enzymes that consist of three domains an N-terminal regulatory ACT domain, a central catalytic domain that includes a non-heme iron at the active... 

Binding of thyinidine-3, 5 -diphosphate (pdTp) and Ca-+ to nuclease induces resistance to proteolysis by a number of proteases (47, 53). Trypsin rapidly cleaves the peptide bond between residues 5 and 6 of the liganded nuclease. The fragment thus formed, nuclease-(6-149), possesses enzymic activity and structure similar to nuclease (48)- Further cleavage of nuclease-(6-149) in the presence of the ligands takes place... 

These experiments became particularly relevant when, in 1974, a surprising observation was made by Manfred Sumper. In series which were diluted so far that in each sample the probability of finding a template molecule was very small, there arose, nonetheless, reproducibly and homogeneously, a molecule with size and structure similar to the midi-... 

All the MIP-QCM chemosensors for biogenic amines above described were quite selective with respect to functionally and structurally similar compounds (inset to Fig. 4). 

The polymer was imprinted with dibenzoyl-methane (42), a 1,3-diketone able to be held in place by formation of a complex with the Co(II) ion, and structurally similar to the product of the cross-aldol condensation. A schematic representation of this approach is given in Scheme 7. 

Klinkert, M.Q., Cioli, D., Shaw, E., Turk, V., Bode, W. and Butler, R. (1 994) Sequence and structure similarities of cathepsin B from the parasite Schistosoma mansoni and human liver. FEBS Letters 351, 397-400. 

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