Coordination of a Water Molecule to a Square-pyramidal N2S3-type Co(III) Complex Directed to an Active Site of Nitrile Hydratase

2005 ◽  
Vol 34 (1) ◽  
pp. 18-19 ◽  
Author(s):  
Tomohiro Ozawa ◽  
Tomohiro Ikeda ◽  
Takuma Yano ◽  
Hidekazu Arii ◽  
Syuhei Yamaguchi ◽  
...  
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Nitrile Hydratase

scholarly journals Fe(2)OG: an integrated HMM profile-based web server to predict and analyze putative non-haem iron(II)- and 2-oxoglutarate-dependent dioxygenase function in protein sequences

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Siddhartha Kundu
Keyword(s):  
Amino Acid ◽  
Water Molecule ◽  
Active Site ◽  
Ferrous Iron ◽  
Web Server ◽  
Protein Sequences ◽  
Diverse Group ◽  
And Function ◽  
Functionally Diverse ◽  
Haem Iron

Abstract Objective Non-haem iron(II)- and 2-oxoglutarate-dependent dioxygenases (i2OGdd), are a taxonomically and functionally diverse group of enzymes. The active site comprises ferrous iron in a hexa-coordinated distorted octahedron with the apoenzyme, 2-oxoglutarate and a displaceable water molecule. Current information on novel i2OGdd members is sparse and relies on computationally-derived annotation schema. The dissimilar amino acid composition and variable active site geometry thereof, results in differing reaction chemistries amongst i2OGdd members. An additional need of researchers is a curated list of sequences with putative i2OGdd function which can be probed further for empirical data. Results This work reports the implementation of $$Fe\left(2\right)OG$$ F e 2 O G , a web server with dual functionality and an extension of previous work on i2OGdd enzymes $$\left(Fe\left(2\right)OG\equiv \{H2OGpred,DB2OG\}\right)$$ F e 2 O G ≡ { H 2 O G p r e d , D B 2 O G } . $$Fe\left(2\right)OG$$ F e 2 O G , in this form is completely revised, updated (URL, scripts, repository) and will strengthen the knowledge base of investigators on i2OGdd biochemistry and function. $$Fe\left(2\right)OG$$ F e 2 O G , utilizes the superior predictive propensity of HMM-profiles of laboratory validated i2OGdd members to predict probable active site geometries in user-defined protein sequences. $$Fe\left(2\right)OG$$ F e 2 O G , also provides researchers with a pre-compiled list of analyzed and searchable i2OGdd-like sequences, many of which may be clinically relevant. $$Fe(2)OG$$ F e ( 2 ) O G , is freely available (http://204.152.217.16/Fe2OG.html) and supersedes all previous versions, i.e., H2OGpred, DB2OG.

Structure-Based Design of Potent Inhibitors of Scytalone Dehydratase:  Displacement of a Water Molecule from the Active Site‡

Biochemistry ◽  
1998 ◽  
Vol 37 (51) ◽  
pp. 17735-17744 ◽  
Author(s):  
James M. Chen ◽  
Simon L. Xu ◽  
Zdzislaw Wawrzak ◽  
Gregory S. Basarab ◽  
Douglas B. Jordan
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Scytalone Dehydratase

scholarly journals Identification of an Active Site-bound Nitrile Hydratase Intermediate through Single Turnover Stopped-flow Spectroscopy

2013 ◽  
Vol 288 (22) ◽  
pp. 15532-15536 ◽  
Author(s):  
Natalie Gumataotao ◽  
Misty L. Kuhn ◽  
Natalia Hajnas ◽  
Richard C. Holz
Keyword(s):  
Active Site ◽  
Nitrile Hydratase ◽  
Stopped Flow ◽  
Single Turnover

scholarly journals Structure-Function Analysis Indicates that an Active-Site Water Molecule Participates in Dimethylsulfoniopropionate Cleavage by DddK

2019 ◽  
Vol 85 (8) ◽  
Author(s):  
Ming Peng ◽  
Xiu-Lan Chen ◽  
Dian Zhang ◽  
Xiu-Juan Wang ◽  
Ning Wang ◽  
...  
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Dimethyl Sulfide ◽  
Catalytic Mechanism ◽  
Heterotrophic Bacteria ◽  
Function Analysis ◽  
Cloud Condensation Nuclei ◽  
Oxidation Products ◽  
Condensation Nuclei ◽  
Marine Heterotrophic Bacteria

ABSTRACT The osmolyte dimethylsulfoniopropionate (DMSP) is produced in petagram quantities in marine environments and has important roles in global sulfur and carbon cycling. Many marine microorganisms catabolize DMSP via DMSP lyases, generating the climate-active gas dimethyl sulfide (DMS). DMS oxidation products participate in forming cloud condensation nuclei and, thus, may influence weather and climate. SAR11 bacteria are the most abundant marine heterotrophic bacteria; many of them contain the DMSP lyase DddK, and their dddK transcripts are relatively abundant in seawater. In a recently described catalytic mechanism for DddK, Tyr64 is predicted to act as the catalytic base initiating the β-elimination reaction of DMSP. Tyr64 was proposed to be deprotonated by coordination to the metal cofactor or its neighboring His96. To further probe this mechanism, we purified and characterized the DddK protein from Pelagibacter ubique strain HTCC1062 and determined the crystal structures of wild-type DddK and its Y64A and Y122A mutants (bearing a change of Y to A at position 64 or 122, respectively), where the Y122A mutant is complexed with DMSP. The structural and mutational analyses largely support the catalytic role of Tyr64, but not the method of its deprotonation. Our data indicate that an active water molecule in the active site of DddK plays an important role in the deprotonation of Tyr64 and that this is far more likely than coordination to the metal or His96. Sequence alignment and phylogenetic analysis suggest that the proposed catalytic mechanism of DddK has universal significance. Our results provide new mechanistic insights into DddK and enrich our understanding of DMS generation by SAR11 bacteria. IMPORTANCE The climate-active gas dimethyl sulfide (DMS) plays an important role in global sulfur cycling and atmospheric chemistry. DMS is mainly produced through the bacterial cleavage of marine dimethylsulfoniopropionate (DMSP). When released into the atmosphere from the oceans, DMS can be photochemically oxidized into DMSO or sulfate aerosols, which form cloud condensation nuclei that influence the reflectivity of clouds and, thereby, global temperature. SAR11 bacteria are the most abundant marine heterotrophic bacteria, and many of them contain DMSP lyase DddK to cleave DMSP, generating DMS. In this study, based on structural analyses and mutational assays, we revealed the catalytic mechanism of DddK, which has universal significance in SAR11 bacteria. This study provides new insights into the catalytic mechanism of DddK, leading to a better understanding of how SAR11 bacteria generate DMS.

Effect of an Asymmetrically Arranged Equatorial Chelate Ring in an Active Site of Nitrile Hydratase

2008 ◽  
Vol 37 (1) ◽  
pp. 66-67 ◽  
Author(s):  
Takuma Yano ◽  
Yuko Wasada-Tsutsui ◽  
Yuji Kajita ◽  
Tomonori Shibayama ◽  
Yasuhiro Funahasi ◽  
...  
Keyword(s):  
Active Site ◽  
Nitrile Hydratase ◽  
Chelate Ring

scholarly journals Mutagenesis and crystallographic studies of the catalytic residues of the papain family protease bleomycin hydrolase: new insights into active-site structure

2006 ◽  
Vol 401 (2) ◽  
pp. 421-428 ◽  
Author(s):  
Paul A. O'Farrell ◽  
Leemor Joshua-Tor
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Bound Water ◽  
Active Site Residues ◽  
Site Structure ◽  
Active Site Cysteine ◽  
C Terminus ◽  
Bleomycin Hydrolase ◽  
Active Site Mutants

Bleomycin hydrolase (BH) is a hexameric papain family cysteine protease which is involved in preparing peptides for antigen presentation and has been implicated in tumour cell resistance to bleomycin chemotherapy. Structures of active-site mutants of yeast BH yielded unexpected results. Replacement of the active-site asparagine with alanine, valine or leucine results in the destabilization of the histidine side chain, demonstrating unambiguously the role of the asparagine residue in correctly positioning the histidine for catalysis. Replacement of the histidine with alanine or leucine destabilizes the asparagine position, indicating a delicate arrangement of the active-site residues. In all of the mutants, the C-terminus of the protein, which lies in the active site, protrudes further into the active site. All mutants were compromised in their catalytic activity. The structures also revealed the importance of a tightly bound water molecule which stabilizes a loop near the active site and which is conserved throughout the papain family. It is displaced in a number of the mutants, causing destabilization of this loop and a nearby loop, resulting in a large movement of the active-site cysteine. The results imply that this water molecule plays a key structural role in this family of enzymes.

scholarly journals Comparison of a retroviral protease in monomeric and dimeric states

2019 ◽  
Vol 75 (10) ◽  
pp. 904-917 ◽  
Author(s):  
Stanislaw Wosicki ◽  
Miroslaw Gilski ◽  
Helena Zabranska ◽  
Iva Pichova ◽  
Mariusz Jaskolski
Keyword(s):  
Water Molecule ◽  
Active Site ◽  
Biochemical Characterization ◽  
Extreme Case ◽  
Loop Region ◽  
Reducing Conditions ◽  
Crystallization Experiment ◽  
Dimeric Form ◽  
Retroviral Proteases ◽  
Interactive 3D

Retroviral proteases (RPs) are of high interest owing to their crucial role in the maturation process of retroviral particles. RPs are obligatory homodimers, with a pepsin-like active site built around two aspartates (in DTG triads) that activate a water molecule, as the nucleophile, under two flap loops. Mason–Pfizer monkey virus (M-PMV) is unique among retroviruses as its protease is also stable in the monomeric form, as confirmed by an existing crystal structure of a 13 kDa variant of the protein (M-PMV PR) and its previous biochemical characterization. In the present work, two mutants of M-PMV PR, D26N and C7A/D26N/C106A, were crystallized in complex with a peptidomimetic inhibitor and one mutant (D26N) was crystallized without the inhibitor. The crystal structures were solved at resolutions of 1.6, 1.9 and 2.0 Å, respectively. At variance with the previous study, all of the new structures have the canonical dimeric form of retroviral proteases. The protomers within a dimer differ mainly in the flap-loop region, with the most extreme case observed in the apo structure, in which one flap loop is well defined while the other flap loop is not defined by electron density. The presence of the inhibitor molecules in the complex structures was assessed using polder maps, but some details of their conformations remain ambiguous. In all of the presented structures the active site contains a water molecule buried deeply between the Asn26-Thr27-Gly28 triads of the protomers. Such a water molecule is completely unique not only in retropepsins but also in aspartic proteases in general. The C7A and C106A mutations do not influence the conformation of the protein. The Cys106 residue is properly placed at the homodimer interface area for a disulfide cross-link, but the reducing conditions of the crystallization experiment prevented S—S bond formation. An animated Interactive 3D Complement (I3DC) is available in Proteopedia at http://proteopedia.org/w/Journal:Acta_Cryst_D:S2059798319011355.

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