Structural Analysis of the Active Site of Porcine Pancreatic Elastase Based on the X-ray Crystal Structures of Complexes with Trifluoroacetyl-Dipeptide-Anilide Inhibitors

Biochemistry ◽  
1995 ◽  
Vol 34 (10) ◽  
pp. 3193-3203 ◽  
Author(s):  
Carla Mattos ◽  
Debra Ann Giammona ◽  
Gregory A. Petsko ◽  
Dagmar Ringe
Keyword(s):  
Structural Analysis ◽  
Crystal Structures ◽  
Active Site ◽  
Pancreatic Elastase ◽  
X Ray ◽  
Porcine Pancreatic Elastase

scholarly journals Structure based protein engineering to confer selectivity of guanine deaminase

2014 ◽  
Vol 70 (a1) ◽  
pp. C437-C437
Author(s):  
Aruna Bitra ◽  
Ruchi Anand
Keyword(s):  
Crystal Structures ◽  
Active Site ◽  
Catalytic Mechanism ◽  
Catalytic Efficiency ◽  
Structural Basis ◽  
Active Site Residues ◽  
X Ray ◽  
Secondary Activity ◽  
Guanine Deaminase ◽  
Differential Selectivity

Guanine deaminases (GDs) are important enzymes involved in both purine metabolism and nucleotide anabolism pathways. Here we present the molecular and catalytic mechanism of NE0047 and use the information obtained to engineer specific enzyme activities. NE0047 from Nitrosomonas europaea was found to be a high fidelity guanine deaminase (catalytic efficiency of 1.2 × 105 M–1 s–1). However; it exhibited secondary activity towards the structurally non-analogous triazine based compound ammeline. The X-ray structure of NE0047 in the presence of the substrate analogue 8-azaguanine help establish that the enzyme exists as a biological dimer and both the proper closure of the C-terminal loop and cross talk via the dimeric interface is crucial for conferring catalytic activity. It was further ascertained that the highly conserved active site residues Glu79 and Glu143 facilitate the deamination reaction by serving as proton shuttles. Moreover, to understand the structural basis of dual substrate specificity, X-ray structures of NE0047 in complex with a series of nucleobase analogs, nucleosides and substrate ammeline were determined. The crystal structures demonstrated that any substitutions in the parent substrates results in the rearrangement of the ligand in a catalytically unfavorable orientation and also impede the closure of catalytically important loop, thereby abrogating activity. However, ammeline was able to adopt a catalytically favorable orientation which, also allowed for proper loop closure. Based on the above knowledge of the crystal structures and the catalytic mechanism, the active site was subsequently engineered to fine-tune NE0047 activity. The mutated versions of the enzyme were designed so that they can function either exclusively as a GD or serve as specific ammeline deaminases. For example, mutations in the active site E143D and N66A confer the enzyme to be an unambiguous GD with no secondary activity towards ammeline. On the other hand, the N66Q mutant of NE0047 only deaminates ammeline. Additionally, a series of crystal structures of the mutant versions were solved that shed light on the structural basis of this differential selectivity.

X-ray diffraction analysis of the inhibition of porcine pancreatic elastase by a peptidyl trifluoromethylketone

1988 ◽  
Vol 201 (2) ◽  
pp. 423-428 ◽  
Author(s):  
Lori H. Takahashi ◽  
R. Radhakrishnan ◽  
Richard E. Rosenfield ◽  
Edgar F. Meyer ◽  
Diane Amy Trainor ◽  
...  
Keyword(s):  
Diffraction Analysis ◽  
X Ray Diffraction ◽  
Pancreatic Elastase ◽  
X Ray ◽  
Porcine Pancreatic Elastase

X-ray crystal structures of active site mutants of the vanadium-containing chloroperoxidase from the fungus Curvularia inaequalis

1999 ◽  
Vol 4 (2) ◽  
pp. 209-219 ◽  
Author(s):  
Sandra Macedo-Ribeiro ◽  
Wieger Hemrika ◽  
Rokus Renirie ◽  
Ron Wever ◽  
A. Messerschmidt
Keyword(s):  
Crystal Structures ◽  
Active Site ◽  
X Ray ◽  
Active Site Mutants

Darstellung und Kristallstrukturen von Phenyliodoantimonaten(III). Strukturkorrelation für Halogenoantimonate(III) / Preparation and Crystal Structures of Phenyliodoantimonates(III). Structural Correlation for Haloantimonates(III)

1991 ◽  
Vol 46 (5) ◽  
pp. 639-646 ◽  
Author(s):  
W. S. Sheldrick ◽  
C. Martin
Keyword(s):  
Structural Analysis ◽  
Crystal Structures ◽  
Iodine Atom ◽  
Trans Position ◽  
X Ray ◽  
Trigonal Bipyramidal ◽  
Structural Correlation ◽  
Bipyramidal Structure ◽  
In Trans

The phenyliodoantimonates(III) [Et4N][Ph2SbI2] (1), [Et4N]2[Ph2Sb2I6] (2) and [Hpy]3[Ph2Sb2I7] (3) have been prepared and their structures established by X-ray structural analysis. The anion [Ph2SbI2]⁻ displays a ψ-trigonal bipyramidal structure with axial Sb–I distances of 2.925(1) and 3.109(1) A. In the dimeric anions [Ph2Sb2I6]2- and [Ph2Sb2I7]3- the antimony atoms exhibit ψ-octahedral geometries. As observed for [Ph2SbI2]⁻, terminal Sb–I bonds in trans-position to one another display significantly different lengths. The anion [Ph2Sb2I7]3- displays Ci- symmetry with a bridging iodine atom at the crystallographic centre of symmetry. Long Sb—I distances of 3.404(1) A are observed to this atom. A structural correlation of opposite Sb–X distances (X = Cl, Br, I) in linear three centre X–Sb ··· X interactions is presented. The sum of the bond valences in iodoantimonates(III) is a minimum for symmetrical I–Sb–I three centre bonds, reflecting thereby the antibonding influence of the Sb 5 s-orbital. This influence is considerably smaller for bromoantimonates(III) and may be effectively neglected for chloroantimonates(III).

X-ray Structural Analysis for the Prediction on the Nature of the Retro Diels - Alder Pathway: Concerted or Stepwise. Structural Studies on Nitrosobenzene Cycloadducts

2009 ◽  
Vol 62 (12) ◽  
pp. 1695 ◽  
Author(s):  
Jesse Roth-Barton ◽  
Jonathan M. White
Keyword(s):  
Structural Analysis ◽  
Crystal Structures ◽  
Diels Alder ◽  
Structure Parameters ◽  
Structural Studies ◽  
Structural Effects ◽  
X Ray ◽  
Early Stages ◽  
Clear Differentiation

Crystal structures of nitrosobenzene cycloadducts 5–7 reveal structural effects consistent with the early stages of the retro Diels–Alder fragmentation. There is a clear differentiation between the structure parameters of cycloadduct 5, which reacts by a concerted synchronous pathway and that of cycloadduct 6, which must react by a two-step pathway. Based on these data, cycloadduct 7 is predicted to react by a highly asynchronous or two-step pathway.

Synthesis of new platinum(II) complexes containing hybrid thioether–pyrazole ligands: Structural analysis by 1H and 13C{1H} NMR spectroscopy and X-ray crystal structures

2007 ◽  
Vol 360 (6) ◽  
pp. 2071-2082 ◽  
Author(s):  
Antonio de Leon ◽  
Josefina Pons ◽  
Jordi García-Antón ◽  
Xavier Solans ◽  
Mercè Font-Bardia ◽  
...  
Keyword(s):  
Nmr Spectroscopy ◽  
Structural Analysis ◽  
Crystal Structures ◽  
1H Nmr ◽  
1H Nmr Spectroscopy ◽  
X Ray ◽  
Pyrazole Ligands
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