scholarly journals Strength and Character of R–X···π Interactions Involving Aromatic Amino Acid Sidechains in Protein-Ligand Complexes Derived from Crystal Structures in the Protein Data Bank

Crystals ◽  
2017 ◽  
Vol 7 (9) ◽  
pp. 273 ◽  
Author(s):  
Kevin Riley ◽  
Khanh-An Tran
Keyword(s):  
Amino Acid ◽  
Crystal Structures ◽  
Protein Data Bank ◽  
Aromatic Amino Acid ◽  
Data Bank ◽  
Π Interactions

scholarly journals Validation and correction of Zn–Cys x His y complexes

2016 ◽  
Vol 72 (10) ◽  
pp. 1110-1118 ◽  
Author(s):  
Wouter G. Touw ◽  
Bart van Beusekom ◽  
Jochem M. G. Evers ◽  
Gert Vriend ◽  
Robbie P. Joosten
Keyword(s):  
Crystal Structures ◽  
Protein Data Bank ◽  
Model Validation ◽  
Data Bank ◽  
Zinc Complexes ◽  
Zinc Ions ◽  
Tetrahedral Complex ◽  
Context Sensitive

Many crystal structures in the Protein Data Bank contain zinc ions in a geometrically distorted tetrahedral complex with four Cys and/or His ligands. A method is presented to automatically validate and correct these zinc complexes. Analysis of the corrected zinc complexes shows that the average Zn–Cys distances and Cys–Zn–Cys angles are a function of the number of cysteines and histidines involved. The observed trends can be used to develop more context-sensitive targets for model validation and refinement.

scholarly journals Conformation-dependent restraints for polynucleotides: the sugar moiety

2019 ◽  
Vol 48 (2) ◽  
pp. 962-973
Author(s):  
Marcin Kowiel ◽  
Dariusz Brzezinski ◽  
Miroslaw Gilski ◽  
Mariusz Jaskolski
Keyword(s):  
Nucleic Acids ◽  
Crystal Structures ◽  
Protein Data Bank ◽  
Data Bank ◽  
Experimental Methods ◽  
Side Chain ◽  
Torsion Angles ◽  
Sugar Moiety ◽  
Structural Database ◽  
Different Parts

Abstract Stereochemical restraints are commonly used to aid the refinement of macromolecular structures obtained by experimental methods at lower resolution. The standard restraint library for nucleic acids has not been updated for over two decades and needs revision. In this paper, geometrical restraints for nucleic acids sugars are derived using information from high-resolution crystal structures in the Cambridge Structural Database. In contrast to the existing restraints, this work shows that different parts of the sugar moiety form groups of covalent geometry dependent on various chemical and conformational factors, such as the type of ribose or the attached nucleobase, and ring puckering or rotamers of the glycosidic (χ) or side-chain (γ) torsion angles. Moreover, the geometry of the glycosidic link and the endocyclic ribose bond angles are functionally dependent on χ and sugar pucker amplitude (τm), respectively. The proposed restraints have been positively validated against data from the Nucleic Acid Database, compared with an ultrahigh-resolution Z-DNA structure in the Protein Data Bank, and tested by re-refining hundreds of crystal structures in the Protein Data Bank. The conformation-dependent sugar restraints presented in this work are publicly available in REFMAC, PHENIX and SHELXL format through a dedicated RestraintLib web server with an API function.

scholarly journals IMAAAGINE: a webserver for searching hypothetical 3D amino acid side chain arrangements in the Protein Data Bank

2013 ◽  
Vol 41 (W1) ◽  
pp. W432-W440 ◽  
Author(s):  
Nurul Nadzirin ◽  
Peter Willett ◽  
Peter J. Artymiuk ◽  
Mohd Firdaus-Raih
Keyword(s):  
Amino Acid ◽  
Protein Data Bank ◽  
Data Bank ◽  
Side Chain ◽  
Amino Acid Side Chain

Use of Patterson-based methods automatically to determine the structures of heavy-atom-containing proteins with up to 6000 non-hydrogen atoms in the asymmetric unit

2006 ◽  
Vol 39 (5) ◽  
pp. 728-734 ◽  
Author(s):  
Maria Cristina Burla ◽  
Rocco Caliandro ◽  
Benedetta Carrozzini ◽  
Giovanni Luca Cascarano ◽  
Liberato De Caro ◽  
...  
Keyword(s):  
Crystal Structures ◽  
Protein Data Bank ◽  
Heavy Atom ◽  
Data Bank ◽  
Atomic Resolution ◽  
Asymmetric Unit ◽  
Hydrogen Atoms ◽  
Heavy Atoms ◽  
Density Maps ◽  
Resolution Data

The Patterson superposition methods described by Burlaet al.[J. Appl. Cryst.(2006),39, 527–535], based on the use of the `multiple implication functions', have been enriched by supplementary filtering techniques based on some general (resolution-dependent) features of both the Patterson and the electron density maps. The method has been implemented in a modified version of the programSIR2004and tested using a set of 20 crystal structures selected from the Protein Data Bank, having a number of non-hydrogen atoms in the asymmetric unit larger than 2000, atomic resolution data and some heavy atoms (equal to or heavier than Ca). The new phasing procedure is able to solve most of the test structures, among which there are two proteins with more than 6000 non-hydrogen atoms in the asymmetric unit, so extending by far the complexity today commonly considered as the limit for Patterson-based methods (i.e.about 2000 non-hydrogen atoms).

Bond-valence analyses of the crystal structures of FeMo/V cofactors in FeMo/V proteins

2020 ◽  
Vol 76 (5) ◽  
pp. 428-437 ◽  
Author(s):  
Wan-Ting Jin ◽  
Min Yang ◽  
Shuang-Shuang Zhu ◽  
Zhao-Hui Zhou
Keyword(s):  
Error Analysis ◽  
Crystal Structures ◽  
Protein Data Bank ◽  
Data Bank ◽  
Bond Valence ◽  
Crystallographic Data ◽  
Data Sets ◽  
Electron Configuration ◽  
The Individual ◽  
Bond Valence Method

The bond-valence method has been used for valence calculations of FeMo/V cofactors in FeMo/V proteins using 51 crystallographic data sets of FeMo/V proteins from the Protein Data Bank. The calculations show molybdenum(III) to be present in MoFe7S9C(Cys)(HHis)[R-(H)homocit] (where H4homocit is homocitric acid, HCys is cysteine and HHis is histidine) in FeMo cofactors, while vanadium(III) with a more reduced iron complement is obtained for FeV cofactors. Using an error analysis of the calculated valences, it was found that in FeMo cofactors Fe1, Fe6 and Fe7 can be unambiguously assigned as iron(III), while Fe2, Fe3, Fe4 and Fe5 show different degrees of mixed valences for the individual Fe atoms. For the FeV cofactors in PDB entry 5n6y, Fe4, Fe5 and Fe6 correspond to iron(II), iron(II) and iron(III), respectively, while Fe1, Fe2, Fe3 and Fe7 exhibit strongly mixed valences. Special situations such as CO-bound and selenium-substituted FeMo cofactors and O(N)H-bridged FeV cofactors are also discussed and suggest rearrangement of the electron configuration on the substitution of the bridging S atoms.

Crystal structures of N6-modified-amino acid related nucleobase analogs (II): hybrid adenine-β-alanine and adenine-GABA molecules

2019 ◽  
Vol 43 (24) ◽  
pp. 9680-9688 ◽  
Author(s):  
Angel García-Raso ◽  
Angel Terrón ◽  
Adela López-Zafra ◽  
Andrés García-Viada ◽  
Agostina Barta ◽  
...  
Keyword(s):  
Amino Acid ◽  
Dft Calculations ◽  
Crystal Structures ◽  
X Ray ◽  
Π Interactions ◽  
X Ray Crystallography

H-Bonding networks and anion–π interactions in the crystal structures of N6-modified-amino acid adenine analogs are investigated using X-ray crystallography and DFT calculations.

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