Geometry glutamic acid

The 2.0 A electron density map of carboxypeptidase A shows three zinc-protein contacts (91). The ligands have been identified as histidine-69, glutamic acid-72 and histidine-196 (91, 101), where the numbers indicate the positions of the residues in the sequence counted from the N-terminal end. The geometry of the complex is irregular but resembles a distorted tetrahedron with an open position directed towards the active site pocket, and presumably occupied by water in the resting enzyme (91). The similarity with the tentative structure of the metal-binding site in carbonic anhydrase is striking. 

In our GA structure solution calculations for both polymorphs, the structural fragment comprised all non-hydrogen atoms of the L-glutamic acid molecule (Fig. 3b). Standard geometries (bond lengths and bond angles) were used, with... 

Clan SC peptidases are a/p hydrolase-fold enzymes that consist of parallel P-strands surrounded by a-helices. The a/p hydrolase-fold provides a versatile catalytic platform that, in addition to achieving proteolytic activity, can either act as an esterase, lipase, dehalogenase, haloperoxidase, lyase, or epoxide hydrolase (18). Six phylogenetically distinct families of clan SC are known, and oifly four of them have known structure. Catalytic amenability of the a/p hydrolase-fold may underlie why clan SC peptidases are the second largest family of serine peptidases in the human genome. Other mechanistic classes need not use the catalytic serine and instead use cysteine or glutamic acid (19). Clan SC peptidases present an identical geometry to the catalytic triad observed in clans PA and SB, yet this constellation is ordered differently in the polypeptide sequence. Substrate selectivity develops from the a-helices that surround the central P-sheet core. Within clan SC, carboxypeptidases from family SIO are unique for their ability to maintain... 

Fig. V-26. (A) Location of the two Fe-S clusters with respect to the amino acid sequence of fenedo.xin from Azoiobacter vinelardii. The 3Fe-3S cluster is ligated by cysteines 8,11,16,20 and 40 and a sixth ligand which is either glutamic acid IS or an exogenous small molecule. The 4Fe-4S cluster is ligated by cysteines 24,39,42 and 45. (B) View of the 3Fe-3S duster showing near planarity of the Fe-S core and distorted tetrahedral geometry about each Fe center (reproduced with permission). ...

Loos PF et al (2008) Theoretical investigation of the geometries and UV-vis spectra of poly (L-glutamic acid) featuring a photochromic azobenzene side chain. J Chem Theory Comput 4 637-645... 

In fact, for random-coil conformations, b in Equation 41 is explicitly related to the exponent in the Mark-Houwink equation by 3b = a 1. In this way values of M may be determined directly from measurements of D° provided KD and b are known. Although both these parameters could in principle be calculated from a detailed knowledge of the geometry of the solute, it is usual to regard them as experimentally determinable parameters. A similar relationship has also been found to hold true for the polypeptide poly(y-benzyl L-glutamate) (PBLG) dissolved both in 1,2-dichloroethane and in dichloroacetic acid. These results are shown in Figures 6 and 7, respectively. 

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