scholarly journals Understanding Structural Features of Microbial Lipases–-An Overview

2008 ◽  
Vol 3 ◽  
pp. ACI.S551 ◽  
Author(s):  
John Geraldine Sandana Mala ◽  
Satoru Takeuchi

The structural elucidations of microbial lipases have been of prime interest since the 1980s. Knowledge of structural features plays an important role in designing and engineering lipases for specific purposes. Significant structural data have been presented for few microbial lipases, while, there is still a structure-deficit, that is, most lipase structures are yet to be resolved. A search for ‘lipase structure’ in the RCSB Protein Data Bank ( http://www.rcsb.org/pdb/ ) returns only 93 hits (as of September 2007) and, the NCBI database ( http://www.ncbi.nlm.nih.gov ) reports 89 lipase structures as compared to 14719 core nucleotide records. It is therefore worthwhile to consider investigations on the structural analysis of microbial lipases. This review is intended to provide a collection of resources on the instrumental, chemical and bioinformatics approaches for structure analyses. X-ray crystallography is a versatile tool for the structural biochemists and is been exploited till today. The chemical methods of recent interests include molecular modeling and combinatorial designs. Bioinformatics has surged striking interests in protein structural analysis with the advent of innumerable tools. Furthermore, a literature platform of the structural elucidations so far investigated has been presented with detailed descriptions as applicable to microbial lipases. A case study of Candida rugosa lipase (CRL) has also been discussed which highlights important structural features also common to most lipases. A general profile of lipase has been vividly described with an overview of lipase research reviewed in the past.

Author(s):  
Jared M Sagendorf ◽  
Nicholas Markarian ◽  
Helen M Berman ◽  
Remo Rohs

Abstract DNAproDB (https://dnaprodb.usc.edu) is a web-based database and structural analysis tool that offers a combination of data visualization, data processing and search functionality that improves the speed and ease with which researchers can analyze, access and visualize structural data of DNA–protein complexes. In this paper, we report significant improvements made to DNAproDB since its initial release. DNAproDB now supports any DNA secondary structure from typical B-form DNA to single-stranded DNA to G-quadruplexes. We have updated the structure of our data files to support complex DNA conformations, multiple DNA–protein complexes within a DNAproDB entry and model indexing for analysis of ensemble data. Support for chemically modified residues and nucleotides has been significantly improved along with the addition of new structural features, improved structural moiety assignment and use of more sequence-based annotations. We have redesigned our report pages and search forms to support these enhancements, and the DNAproDB website has been improved to be more responsive and user-friendly. DNAproDB is now integrated with the Nucleic Acid Database, and we have increased our coverage of available Protein Data Bank entries. Our database now contains 95% of all available DNA–protein complexes, making our tools for analysis of these structures accessible to a broad community.


Biocatalysis ◽  
1994 ◽  
Vol 9 (1-4) ◽  
pp. 209-225 ◽  
Author(s):  
Sharmin N. Ahmed ◽  
Romas J. Kazlauskas ◽  
Anne H. Morinville ◽  
Pawel Grochulski ◽  
Joseph D. Schrag ◽  
...  

2017 ◽  
Author(s):  
Dinakar M. Salunke

AbstractStructure determination utilizing X-ray crystallography involves collection of diffraction data, determination of initial phases followed by iterative rounds of model building and crystallographic refinement to improve the phases and minimize the differences between calculated and observed structure factors. At each of these stages, a variety of statistical filters exist to ensure appropriate validation. Biologically important observations often come from interpretations of signals that need to be carefully deciphered from noise and therefore human intervention is as important as the automated filters. Currently, all structural data are deposited in the Protein Data Bank and this repository is continuously evolving to incorporate possible new improvements in macromolecular crystallography. The journals that publish data arising from structural studies modulate their policies to take cognizance of new improved methodologies. The PDB and journals have evolved an accepted protocol to ensure the integrity of crystallographic results. As a result, the quality of available data and interpretations are becoming better over the years. However, there have been periodic efforts by some individuals who misuse validation mechanisms to selectively target published research through spurious challenges. These actions do more harm to the field of structural biology and runs counter to their claim to cleanse the system. The scientific systems in structural biology are robust and capable of self-correction and unwarranted vigilantism is counterproductive.


Author(s):  
Michael Duszenko ◽  
Lars Redecke ◽  
Celestin Nzanzu Mudogo ◽  
Benjamin Philip Sommer ◽  
Stefan Mogk ◽  
...  

During the last decade, the number of three-dimensional structures solved by X-ray crystallography has increased dramatically. By 2014, it had crossed the landmark of 100 000 biomolecular structures deposited in the Protein Data Bank. This tremendous increase in successfully crystallized proteins is primarily owing to improvements in cloning strategies, the automation of the crystallization process and new innovative approaches to monitor crystallization. However, these improvements are mainly restricted to soluble proteins, while the crystallization and structural analysis of membrane proteins or proteins that undergo major post-translational modifications remains challenging. In addition, the need for relatively large crystals for conventional X-ray crystallography usually prevents the analysis of dynamic processes within cells. Thus, the advent of high-brilliance synchrotron and X-ray free-electron laser (XFEL) sources and the establishment of serial crystallography (SFX) have opened new avenues in structural analysis using crystals that were formerly unusable. The successful structure elucidation of cathepsin B, accomplished by the use of microcrystals obtained byin vivocrystallization in baculovirus-infected Sf9 insect cells, clearly proved that crystals grown intracellularly are very well suited for X-ray analysis. Here, methods by whichin vivocrystals can be obtained, isolated and used for structural analysis by novel highly brilliant XFEL and synchrotron-radiation sources are summarized and discussed.


PLoS ONE ◽  
2021 ◽  
Vol 16 (3) ◽  
pp. e0247335
Author(s):  
Emilia O. Mason ◽  
Yehuda Goldgur ◽  
Dorothea Robev ◽  
Andrew Freywald ◽  
Dimitar B. Nikolov ◽  
...  

Eph receptors are the largest group amongst the receptor tyrosine kinases and are divided into two subgroups, A and B, based on ligand binding specificities and sequence conservation. Through ligand-induced and ligand-independent activities, Ephs play central roles in diverse biological processes, including embryo development, regulation of neuronal signaling, immune responses, vasculogenesis, as well as tumor initiation, progression, and metastasis. The Eph extracellular regions (ECDs) are constituted of multiple domains, and previous structural studies of the A class receptors revealed how they interact with ephrin ligands and simultaneously mediate Eph-Eph clustering necessary for biological activity. Specifically, EphA structures highlighted a model, where clustering of ligand-bound receptors relies on two distinct receptor/receptor interfaces. Interestingly, most unliganded A class receptors also form an additional, third interface, between the ligand binding domain (LBD) and the fibronectin III domain (FN3) of neighboring molecules. Structures of B-class Eph ECDs, on the other hand, have never been reported. To further our understanding of Eph receptor function, we crystallized the EphB6-ECD and determined its three-dimensional structure using X-ray crystallography. EphB6 has important functions in both normal physiology and human malignancies and is especially interesting because this atypical receptor innately lacks kinase activity and our understanding of the mechanism of action is still incomplete. Our structural data reveals the overall EphB6-ECD architecture and shows EphB6-LBD/FN3 interactions similar to those observed for the unliganded A class receptors, suggesting that these unusual interactions are of general importance to the Eph group. We also observe unique structural features, which likely reflect the atypical signaling properties of EphB6, namely the need of co-receptor(s) for this kinase-inactive Eph. These findings provide new valuable information on the structural organization and mechanism of action of the B-class Ephs, and specifically EphB6, which in the future will assist in identifying clinically relevant targets for cancer therapy.


2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Xuesong Wang ◽  
Willem Jespers ◽  
Rubén Prieto-Díaz ◽  
Maria Majellaro ◽  
Adriaan P. IJzerman ◽  
...  

AbstractThe four adenosine receptors (ARs) A1AR, A2AAR, A2BAR, and A3AR are G protein-coupled receptors (GPCRs) for which an exceptional amount of experimental and structural data is available. Still, limited success has been achieved in getting new chemical modulators on the market. As such, there is a clear interest in the design of novel selective chemical entities for this family of receptors. In this work, we investigate the selective recognition of ISAM-140, a recently reported A2BAR reference antagonist. A combination of semipreparative chiral HPLC, circular dichroism and X-ray crystallography was used to separate and unequivocally assign the configuration of each enantiomer. Subsequently affinity evaluation for both A2A and A2B receptors demonstrate the stereospecific and selective recognition of (S)-ISAM140 to the A2BAR. The molecular modeling suggested that the structural determinants of this selectivity profile would be residue V2506.51 in A2BAR, which is a leucine in all other ARs including the closely related A2AAR. This was herein confirmed by radioligand binding assays and rigorous free energy perturbation (FEP) calculations performed on the L249V6.51 mutant A2AAR receptor. Taken together, this study provides further insights in the binding mode of these A2BAR antagonists, paving the way for future ligand optimization.


ChemInform ◽  
2005 ◽  
Vol 36 (23) ◽  
Author(s):  
Smriti Trikha ◽  
Rajesh Kumar ◽  
Ashish Dhawan ◽  
Poonam Poonam ◽  
Ashok K. Prasad ◽  
...  

2018 ◽  
Vol 293 (47) ◽  
pp. 18296-18308 ◽  
Author(s):  
Chelsea Vickers ◽  
Feng Liu ◽  
Kento Abe ◽  
Orly Salama-Alber ◽  
Meredith Jenkins ◽  
...  

Fucoidans are chemically complex and highly heterogeneous sulfated marine fucans from brown macro algae. Possessing a variety of physicochemical and biological activities, fucoidans are used as gelling and thickening agents in the food industry and have anticoagulant, antiviral, antitumor, antibacterial, and immune activities. Although fucoidan-depolymerizing enzymes have been identified, the molecular basis of their activity on these chemically complex polysaccharides remains largely uninvestigated. In this study, we focused on three glycoside hydrolase family 107 (GH107) enzymes: MfFcnA and two newly identified members, P5AFcnA and P19DFcnA, from a bacterial species of the genus Psychromonas. Using carbohydrate-PAGE, we show that P5AFcnA and P19DFcnA are active on fucoidans that differ from those depolymerized by MfFcnA, revealing differential substrate specificity within the GH107 family. Using a combination of X-ray crystallography and NMR analyses, we further show that GH107 family enzymes share features of their structures and catalytic mechanisms with GH29 α-l-fucosidases. However, we found that GH107 enzymes have the distinction of utilizing a histidine side chain as the proposed acid/base catalyst in its retaining mechanism. Further interpretation of the structural data indicated that the active-site architectures within this family are highly variable, likely reflecting the specificity of GH107 enzymes for different fucoidan substructures. Together, these findings begin to illuminate the molecular details underpinning the biological processing of fucoidans.


Sign in / Sign up

Export Citation Format

Share Document