scholarly journals Comparative Structural Analysis of Different Mycobacteriophage-Derived Mycolylarabinogalactan Esterases (Lysin B)

Biomolecules ◽  
2019 ◽  
Vol 10 (1) ◽  
pp. 45 ◽  
Author(s):  
Ahmed H. Korany ◽  
Adel Abouhmad ◽  
Walid Bakeer ◽  
Tamer Essam ◽  
Magdy A. Amin ◽  
...  
Keyword(s):  
Structural Analysis ◽  
Active Site ◽  
Three Dimensional ◽  
3D Models ◽  
Mycolic Acid ◽  
Dimensional Structure ◽  
Multiple Sequence ◽  
Potential Alternative ◽  
Lid Domain ◽  
Long Chain

Mycobacteriophage endolysins have emerged as a potential alternative to the current antimycobacterial agents. This study focuses on mycolylarabinogalactan hydrolase (LysB) enzymes of the α/β-hydrolase family, which disrupt the unique mycolic acid layer of mycobacterium cell wall. Multiple sequence alignment and structural analysis studies showed LysB-D29, the only enzyme with a solved three-dimensional structure, to share several common features with esterases (lacking lid domain) and lipases (acting on long chain lipids). Sequence and structural comparisons of 30 LysB homology models showed great variation in domain organizations and total protein length with major differences in the loop-5 motif harboring the catalytic histidine residue. Docking of different p-nitrophenyl ligands (C4-C18) to LysB-3D models revealed that the differences in length and residues of loop-5 contributed towards wide diversity of active site conformations (long tunnels, deep and superficial funnels, shallow bowls, and a narrow buried cave) resembling that of lipases, cutinases, and esterases. A set of seven LysB enzymes were recombinantly produced; their activity against p-nitrophenyl esters could be related to their active site conformation and acyl binding site. LysB-D29 (long tunnel) showed the highest activity with long chain p-nitrophenyl palmitate followed by LysB-Omega (shallow bowl) and LysB-Saal (deep funnel).

scholarly journals Characterization of a novel lipase from Pseudomonas aeruginosa

2019 ◽  
Vol 18 (1) ◽  
pp. 44-51
Author(s):  
Nodir Sh. Berdiev ◽  
Jamolitdin F. Ziyavitdinov ◽  
Akmal M. Asrorov ◽  
Shukhratjon S. Olimjonov ◽  
Shavkat I. Salikhov
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Amino Acid ◽  
Amino Acid Sequence ◽  
Catalytic Domain ◽  
Three Dimensional ◽  
Enzymatic Digestion ◽  
Dimensional Structure ◽  
Fuel Oils ◽  
Potential Alternative ◽  
Lid Domain

Abstract Lipases cleaving oils into fatty acids and glycerol are of great interest for the use in increasing the efficiency of fuels. In this work, a novel lipase from Pseudomonas aeruginosa, P. aeruginosa A12, was isolated by ion-exchange and hydrophobic chromatography. The purity of lipase was shown by electrophoresis and its molecular weight was estimated to be ~ 31.6 kDa. The whole amino acid sequence was analyzed by an LC-MS/MS method. Temperature- and pH-dependent optimum of the enzyme compiled 30 °C and 7.5, respectively. The obtained enzyme exhibited 79 % similarity of amino acid sequence to a lipase isolated from the same strain of P. aeruginosa. Thus, the novel lipase was determined to belong to I.1 subfamily of bacterial true lipases. Three dimensional structure of the isolated lipase isoform was modeled based on obtained sequences. Amino acids forming the catalytic domain were shown in the model. Lid domain is suggested to be in the open conformation. These results provide a potential alternative for enzymatic digestion of fuel oils and serve for the development of fundamental knowledge of lipase activity.

scholarly journals Identification and “in silico” Structural Analysis of the Glutamine-rich Protein Qrp (YheA) in Staphylococcus Aureus

2019 ◽  
Vol 12 (1) ◽  
pp. 18-29
Author(s):  
Javier Escobar-Perez ◽  
Katterine Ospina-Garcia ◽  
Zayda Lorena Corredor Rozo ◽  
Ricaurte Alejandro Marquez-Ortiz ◽  
Jaime E Castellanos ◽  
...  
Keyword(s):  
Staphylococcus Aureus ◽  
Structural Analysis ◽  
Protein Function ◽  
In Silico ◽  
3D Structure ◽  
Three Dimensional ◽  
3D Models ◽  
Protein Domain ◽  
Dimensional Structure ◽  
Biofilm Growth

Background: YlbF and YmcA are two essential proteins for the formation of biofilm, sporulation, and competence in Bacillus subtilis. In these two proteins, a new protein domain called com_ylbF was recently discovered, but its role and protein function has not yet been established. Objective: In this study, we identified and performed an “in silico” structural analysis of the YheA protein, another com_ylbF-containing protein, in the opportunistic pathogen Staphylococcus aureus. Methods: The search of the yheA gene was performed using BLAST-P and tBLASn algorithms. The three-dimensional (3D) models of YheA, as well as YlbF and YmcA proteins, were built using the I-TASSER and Quark programs. The identification of the native YheA in Staphylococcus aureus was carried out through chromatography using the FPLC system. Results: We found that YheA protein is more widely distributed in Gram-positive bacteria than YlbF and YmcA. Two new and important characteristics for YheA and other com_ylbF-containing proteins were found: a highly conserved 3D structure and the presence of a putative conserved motif located in the central region of the domain, which could be involved in its function. Additionally, we established that Staphylococcus aureus expresses YheA protein in both planktonic growth and biofilm. Finally, we suggest renaming YheA as glutamine-rich protein (Qrp) in S. aureus. Conclusion: The Grp (YheA), YlbF, and YmcA proteins adopt a highly conserved three-dimensional structure, harboring a protein-specific putative motif within the com_ylbF domain, which possibly favors the interaction with their substrates. Finally, Staphylococcus aureus expresses the Grp (YheA) protein in both planktonic and biofilm growth.

Characterization of an A-type cyclin-dependent kinase gene from Dendrobium candidum

Biologia ◽  
2012 ◽  
Vol 67 (2) ◽  
Author(s):  
Gang Zhang ◽  
Chao Song ◽  
Ming-Ming Zhao ◽  
Biao Li ◽  
Shun-Xing Guo
Keyword(s):  
Molecular Mechanisms ◽  
Three Dimensional ◽  
Postembryonic Development ◽  
Kinase Domain ◽  
Dimensional Structure ◽  
Pcr Analysis ◽  
Kinase Gene ◽  
Multiple Sequence ◽  
Dendrobium Candidum ◽  
Rapid Amplification

AbstractCyclin-dependent kinases (CDKs) play an essential role in cell cycle regulation during the embryonic and postembryonic development of organisms. To better understand the molecular mechanisms of CDKs involved in embryogenesis regulation in the endangered medicinal plant Dendrobium candidum Wall. ex Lindl., a 1229-bp full-length cDNA of an A-type CDK gene, Denca;CDKA;1, was identified using 3′ rapid amplification of cDNA end (RACE) PCR. Denca;CDKA;1 was predicted to encode a 294 amino acid residue-long protein of 33.76 kDa with an isoelectric point of 7.72. The deduced Denca;CDKA;1 protein contained a conserved serine/threonine-protein kinase domain (S-TKc) and a canonical cyclinbinding “PSTAIRE” motif. Multiple sequence alignment indicated that members of CDKA family from various plants exhibited a high degree of sequence identity ranging from 82% to 93%. A neighbor-joining phylogenetic tree showed that Denca;CDKA;1 was clustered into the plant group and was distant from the animal and fungal groups. The modeled three-dimensional structure of Denca;CDKA;1 exhibited the similar functional structure of a fold consisting of β-sheets and α-helices joined by discontinuous random coils forming two relatively independent lobes. Quantitative real-time PCR analysis revealed that Denca;CDKA;1 transcripts were the most abundant in protocorm-like bodies with 4.76 fold, followed by that in roots (4.19 fold), seeds (2.57 fold), and stems (1.57 fold). This study characterized the novel Denca;CDKA;1 gene from D. candidum for the first time and the results will be useful for further functional determination of the gene.

scholarly journals Structural Features of a Bacteroidetes-Affiliated Cellulase Linked with a Polysaccharide Utilization Locus

2015 ◽  
Vol 5 (1) ◽  
Author(s):  
A.E. Naas ◽  
A.K. MacKenzie ◽  
B. Dalhus ◽  
V.G.H. Eijsink ◽  
P.B. Pope
Keyword(s):  
Active Site ◽  
Three Dimensional ◽  
Structural Features ◽  
Structure And Function ◽  
Dimensional Structure ◽  
Active Site Cleft ◽  
Polysaccharide Utilization Locus ◽  
And Function ◽  
Rumen Metagenome

Abstract Previous gene-centric analysis of a cow rumen metagenome revealed the first potentially cellulolytic polysaccharide utilization locus, of which the main catalytic enzyme (AC2aCel5A) was identified as a glycoside hydrolase (GH) family 5 endo-cellulase. Here we present the 1.8 Å three-dimensional structure of AC2aCel5A and characterization of its enzymatic activities. The enzyme possesses the archetypical (β/α)8-barrel found throughout the GH5 family and contains the two strictly conserved catalytic glutamates located at the C-terminal ends of β-strands 4 and 7. The enzyme is active on insoluble cellulose and acts exclusively on linear β-(1,4)-linked glucans. Co-crystallization of a catalytically inactive mutant with substrate yielded a 2.4 Å structure showing cellotriose bound in the −3 to −1 subsites. Additional electron density was observed between Trp178 and Trp254, two residues that form a hydrophobic “clamp”, potentially interacting with sugars at the +1 and +2 subsites. The enzyme’s active-site cleft was narrower compared to the closest structural relatives, which in contrast to AC2aCel5A, are also active on xylans, mannans and/or xyloglucans. Interestingly, the structure and function of this enzyme seem adapted to less-substituted substrates such as cellulose, presumably due to the insufficient space to accommodate the side-chains of branched glucans in the active-site cleft.

PREDICTION OF THE THREE-DIMENSIONAL STRUCTURE OF THE ENZYMATIC PART OF T-PA

1987 ◽  
Author(s):  
A Heckel ◽  
K M Hasselbach
Keyword(s):  
Amino Acids ◽  
Amino Acid ◽  
Active Site ◽  
Serine Proteases ◽  
Three Dimensional ◽  
Amino Acid Sequences ◽  
Dimensional Structure ◽  
Salt Bridges ◽  
Three Dimensional Structure ◽  
Insertions And Deletions

Up to now the three-dimensional structure of t-PA or parts of this enzyme is unknown. Using computer graphical methods the spatial structure of the enzymatic part of t-PA is predicted on the hypothesis, the three-dimensional backbone structure of t-PA being similar to that of other serine proteases. The t-PA model was built up in three steps:1) Alignment of the t-PA sequence with other serine proteases. Comparison of enzyme structures available from Brookhaven Protein Data Bank proved elastase as a basis for modeling.2) Exchange of amino acids of elastase differing from the t-PA sequence. The replacement of amino acids was performed such that backbone atoms overlapp completely and side chains superpose as far as possible.3) Modeling of insertions and deletions. To determine the spatial arrangement of insertions and deletions parts of related enzymes such as chymotrypsin or trypsin were used whenever possible. Otherwise additional amino acid sequences were folded to a B-turn at the surface of the proteine, where all insertions or deletions are located. Finally the side chain torsion angles of amino acids were optimised to prevent close contacts of neigh bouring atoms and to improve hydrogen bonds and salt bridges.The resulting model was used to explain binding of arginine 560 of plasminogen to the active site of t-PA. Arginine 560 interacts with Asp 189, Gly 19 3, Ser 19 5 and Ser 214 of t-PA (chymotrypsin numbering). Furthermore interaction of chromo-genic substrate S 2288 with the active site of t-PA was studied. The need for D-configuration of the hydrophobic amino acid at the N-terminus of this tripeptide derivative could be easily explained.

scholarly journals The three-dimensional structure of a class-Pi glutathione S-transferase complexed with glutathione: the active-site hydration provides insights into the reaction mechanism

1998 ◽  
Vol 333 (3) ◽  
pp. 811-816 ◽  
Author(s):  
Antonio PÁRRAGA ◽  
Isabel GARCÍA-SÁEZ ◽  
Sinead B. WALSH ◽  
Timothy J. MANTLE ◽  
Miquel COLL
Keyword(s):  
Conformational Changes ◽  
Active Site ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Water Molecules ◽  
X Ray Diffraction ◽  
Glutathione S Transferase ◽  
X Ray ◽  
The Right

The structure of mouse liver glutathione S-transferase P1-1 complexed with its substrate glutathione (GSH) has been determined by X-ray diffraction analysis. No conformational changes in the glutathione moiety or in the protein, other than small adjustments of some side chains, are observed when compared with glutathione adduct complexes. Our structure confirms that the role of Tyr-7 is to stabilize the thiolate by hydrogen bonding and to position it in the right orientation. A comparison of the enzyme–GSH structure reported here with previously described structures reveals rearrangements in a well-defined network of water molecules in the active site. One of these water molecules (W0), identified in the unliganded enzyme (carboxymethylated at Cys-47), is displaced by the binding of GSH, and a further water molecule (W4) is displaced following the binding of the electrophilic substrate and the formation of the glutathione conjugate. The possibility that one of these water molecules participates in the proton abstraction from the glutathione thiol is discussed.

scholarly journals Structure-function studies of the myosin motor domain: importance of the 50-kDa cleft.

1996 ◽  
Vol 7 (7) ◽  
pp. 1123-1136 ◽  
Author(s):  
K M Ruppel ◽  
J A Spudich
Keyword(s):  
Active Site ◽  
Three Dimensional ◽  
Point Mutations ◽  
Random Mutagenesis ◽  
Motor Domain ◽  
Actin Binding ◽  
Dimensional Structure ◽  
Null Cell ◽  
Myosin Motor Domain ◽  
Cell Phenotypes

We used random mutagenesis to create 21 point mutations in a highly conserved region of the motor domain of Dictyostelium myosin and classified them into three distinct groups based on the ability to complement myosin null cell phenotypes: wild type, intermediate, and null. Biochemical analysis of the mutated myosins also revealed three classes of mutants that correlated well with the phenotypic classification. The mutated myosins that were not fully functional showed defects ranging from ATP nonhydrolyzers to myosins whose enzymatic and mechanical properties are uncoupled. Placement of the mutations onto the three-dimensional structure of myosin showed that the mutated region lay along the cleft that separates the active site from the actin-binding domain and that has been shown to move in response to changes at the active site. These results demonstrate that this region of myosin plays a key role in transduction of chemical energy to mechanical displacement.

Three-dimensional structure of β-momorcharin at 2.55 Å resolution

1999 ◽  
Vol 55 (6) ◽  
pp. 1144-1151 ◽  
Author(s):  
Yu-Ren Yuan ◽  
Yong-Ning He ◽  
Jian-Ping Xiong ◽  
Zong-Xiang Xia
Keyword(s):  
Active Site ◽  
Structural Model ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Molecular Replacement ◽  
Ribosome Inactivating Protein ◽  
Three Dimensional Structure ◽  
Replacement Method ◽  
Enzymatic Function ◽  
Molecular Replacement Method

β-Momorcharin (Mr ≃ 29 kDa) is a single-chained ribosome-inactivating protein (RIP) with a branched hexasaccharide bound to Asn51. The crystal structure of β-momorcharin has been determined using the molecular-replacement method and refined to 2.55 Å resolution. The final structural model gave an R factor of 17.2% and root-mean-square deviations of 0.016 Å and 1.76° from ideal bond lengths and bond angles, respectively. β-Momorcharin contains nine α-helices, two 310 helices and three β-sheets, and its overall structure is similar to those of other single-chained RIPs. Residues Tyr70, Tyr109, Glu158 and Arg161 are expected to define the active site of β-momorcharin as an rRNA N-glycosidase. The oligosaccharide is linked to the protein through an N-glycosidic bond, β-GlcNAc–(1-N)-Asn51, and stretches from the surface of the N-terminal domain far from the active site, which suggests that it should not play a role in enzymatic function. The oligosaccharide of each β-momorcharin molecule interacts with the protein through hydrogen bonds, although in the crystals most of these are intermolecular interactions with the protein atoms in an adjacent unit cell. This is the first example of an RIP structure which provides information about the three-dimensional structure and binding site of the oligosaccharide in the active chains of RIPs.

Static Laue Diffraction Studies on Acetylcholinesterase

1998 ◽  
Vol 54 (6) ◽  
pp. 1359-1366 ◽  
Author(s):  
Raimond B. G. Ravelli ◽  
Mia L. Raves ◽  
Zhong Ren ◽  
Dominique Bourgeois ◽  
Michel Roth ◽  
...  
Keyword(s):  
Structural Change ◽  
Exposure Time ◽  
Active Site ◽  
Three Dimensional ◽  
Dimensional Structure ◽  
Reversible Inhibitor ◽  
Data Set ◽  
Time Resolved ◽  
X Ray ◽  
Density Maps

Acetylcholinesterase (AChE) is one of nature's fastest enzymes, despite the fact that its three-dimensional structure reveals its active site to be deeply sequestered within the molecule. This raises questions with respect to traffic of substrate to, and products from, the active site, which may be investigated by time-resolved crystallography. In order to address one aspect of the feasibility of performing time-resolved studies on AChE, a data set has been collected using the Laue technique on a trigonal crystal of Torpedo californica AChE soaked with the reversible inhibitor edrophonium, using a total X-ray exposure time of 24 ms. Electron-density maps obtained from the Laue data, which are of surprisingly good quality compared with similar maps from monochromatic data, show essentially the same features. They clearly reveal the bound ligand, as well as a structural change in the conformation of the active-site Ser200 induced upon binding.

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