scholarly journals Mapping the substrate specificity of the Plasmodium M1 and M17 aminopeptidases.

2021 ◽  
Author(s):  
Tess R Malcolm ◽  
Karolina W. Swiderska ◽  
Brooke K Hayes ◽  
Chaille T Webb ◽  
Marcin Drag ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Drug Targets ◽  
Protein Production ◽  
Turnover Rate ◽  
Plasmodium Species ◽  
Peptide Sequence ◽  
Sequence Specificity ◽  
Model Species ◽  
Hydrophobic Residues ◽  
Digestion Process

During malarial infection, Plasmodium parasites digest human hemoglobin to obtain free amino acids for protein production and maintenance of osmotic pressure. The Plasmodium M1 and M17 aminopeptidases are both postulated to have an essential role in the terminal stages of the hemoglobin digestion process and are validated drug targets for the design of new dual-target anti-malarial compounds. In this study, we profiled the substrate specificity fingerprints and kinetic behaviors of M1 and M17 aminopeptidases from Plasmodium falciparum and Plasmodium vivax, and the mouse model species, Plasmodium berghei. We found that although the Plasmodium M1 aminopeptidases share a largely similar, broad specificity at the P1 position, the P. falciparum M1 displays the greatest diversity in specificity and P. berghei M1 showing a preference for charged P1 residues. In contrast, the Plasmodium M17 aminopeptidases share a highly conserved preference for hydrophobic residues at the P1 position. The aminopeptidases also demonstrated intra-peptide sequence specificity, particularly the M1 aminopeptidases, which showed a definitive preference for peptides with fewer negatively charged intrapeptide residues. Overall, the P. vivax and P. berghei enzymes had a faster substrate turnover rate than the P. falciparum enzymes, which we postulate is due to subtle differences in structural dynamicity. Together, these results build a kinetic profile that allows us to better understand the catalytic nuances of the M1 and M17 aminopeptidases from different Plasmodium species.

scholarly journals Mapping the substrate sequence and length of the Plasmodium M1 and M17 aminopeptidases

2020 ◽  
Author(s):  
Tess R Malcolm ◽  
Karolina W. Swiderska ◽  
Brooke K Hayes ◽  
Marcin Drag ◽  
Nyssa Drinkwater ◽  
...  
Keyword(s):  
Drug Targets ◽  
Protein Production ◽  
Behavioral Responses ◽  
Peptide Sequence ◽  
Sequence Specificity ◽  
Model Species ◽  
Hydrophobic Residues ◽  
Digestion Process ◽  
Malarial Infection ◽  
Peptide Length

AbstractDuring malarial infection, Plasmodium parasites digest human hemoglobin to obtain free amino acids for protein production and maintenance of osmotic pressure. The Plasmodium M1 and M17 aminopeptidases are both postulated to have an essential role in the terminal stages of the hemoglobin digestion process and are validated drug targets for the design of new dualtarget anti-malarial compounds. In this study, we profiled the substrate specificity fingerprints and kinetic behaviors of M1 and M17 aminopeptidases from Plasmodium falciparum and Plasmodium vivax, and the mouse model species, Plasmodium berghei. We found that although the Plasmodium M1 aminopeptidases share a largely similar, broad specificity at the P1 position, the P. falciparum M1 displays the greatest diversity in specificity and P. berghei M1 showing a preference for charged P1 residues. In contrast, the Plasmodium M17 aminopeptidases share a highly conserved preference for hydrophobic residues at the P1 position. The aminopeptidases also demonstrated intra-peptide sequence specificity, particularly the M1 aminopeptidases, which showed a definitive preference for peptides with fewer negatively charged intrapeptide residues. When tested with a panel of peptides of increasing length, each aminopeptidase exhibited unique catalytic behavioral responses to the increase in peptide length, although all six aminopeptidases exhibited an increase in cooperativity as peptide length increased. Overall the P. vivax and P. berghei enzymes were generally faster than the P. falciparum enzymes, which we postulate is due to subtle differences in structural dynamicity. Together, these results build a kinetic profile that allows us to better understand the catalytic nuances of the M1 and M17 aminopeptidases from different Plasmodium species.

Bimodal evolution of Src and Abl kinase substrate specificity revealed using mammalian cell extract as substrate pool

2020 ◽  
Author(s):  
Patrick Finneran ◽  
Margaret Soucheray ◽  
Christopher Wilson ◽  
Renee Otten ◽  
Vanessa Buosi ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Mammalian Cell ◽  
Tyrosine Kinases ◽  
Cell Extract ◽  
Peptide Sequence ◽  
Last Common Ancestor ◽  
Sequence Specificity ◽  
Kinase Substrate ◽  
Evolutionary Trajectories ◽  
Substrate Proteins

AbstractThe specificity of phosphorylation by protein kinases is essential to the integrity of biological signal transduction. While peptide sequence specificity for individual kinases has been examined previously, here we explore the evolutionary progression that has led to the modern substrate specificity of two non-receptor tyrosine kinases, Abl and Src. To efficiently determine the substrate specificity of modern and reconstructed ancestral kinases, we developed a method using mammalian cell lysate as the substrate pool, thereby representing the naturally occurring substrate proteins. We find that the oldest tyrosine kinase ancestor was a promiscuous enzyme that evolved through a more specific last common ancestor into a specific human Abl. In contrast, the parallel pathway to human Src involved a loss of substrate specificity, leading to general promiscuity. These results add a new facet to our understanding of the evolution of signaling pathways, with both subfunctionalization and neofunctionalization along the evolutionary trajectories.

scholarly journals IN SILICO ANTIMALARIAL TARGET SELECTION CONSERVED IN FOUR PLASMODIUM SPECIES

2020 ◽  
Author(s):  
Oladoja AWofisayo
Keyword(s):  
Comparative Genomics ◽  
Peer Review ◽  
In Silico ◽  
Drug Targets ◽  
Homo Sapiens ◽  
Mammalian Species ◽  
Target Selection ◽  
Plasmodium Species ◽  
Data Bank ◽  
Sequence Motifs

Objectives: The need for new antimalarials drugs and drug targets is pertinent due to the emergence of drug resistant strains of the parasites. Improper target selection has resulted in therapeutic failure. The genomic/post genomic era has made possible the deciphering of the 3D crystal structures of proteins and DNA which are drug targets and are deposited in the protein data bank. Methods: Novel antimalarial targets obtained from evolutionary conserved short sequence motifs are utilised and are essential in transcription processes in the parasite. The motifs TGCATGCA, GTGCAC and GTGCGTGC were curated from experimental work, validated and analysed via phylogenomics genomics and comparative genomics. PlasmoDB blastn was applied to determine their similarity in Plasmodium vivax, knowlesi, Ovale and yoeli. The complete genome of Plasmodium falciparum vivax, knowlesi, Ovale and yoeli was downloaded from the plasmoDB and their positions determined. Results: The targets are essential, conserved in rodent and mammalian species via phylogenomics with percentage identity and similarity greater than 80%, have no similar genes in the same genome and also found to be selective in the parasites vis-à-vis the Homo sapiens via comparative genomics with 0% identity and similarity in the human genome. Conclusion: The targets reveal at the molecular and biochemical level, the vulnerable regions in the parasite while safe in human hence their choices in subsequent rationale drug discovery and design protocols. Peer Review History: Received: 18 July 2020; Revised: 1 October; Accepted: 12 October, Available online: 15 November 2020 UJPR follows the most transparent and toughest ‘Advanced OPEN peer review’ system. The identity of the authors and, reviewers will be known to each other. This transparent process will help to eradicate any possible malicious/purposeful interference by any person (publishing staff, reviewer, editor, author, etc) during peer review. As a result of this unique system, all reviewers will get their due recognition and respect, once their names are published in the papers. We expect that, by publishing peer review reports with published papers, will be helpful to many authors for drafting their article according to the specifications. Auhors will remove any error of their article and they will improve their article(s) according to the previous reports displayed with published article(s). The main purpose of it is ‘to improve the quality of a candidate manuscript’. Our reviewers check the ‘strength and weakness of a manuscript honestly’. There will increase in the perfection, and transparency. Received file Average Peer review marks at initial stage: 5.5/10 Average Peer review marks at publication stage: 7.0/10 Reviewer(s) detail: Dr. Tamer ELHABIBI, ERU University, Egypt, [email protected] Dr. Soroush Sardari, Biotech Pasteur Institute of Iran, Tehran, Iran, [email protected] Comments of reviewer(s): Similar Articles: IN SILICO LIGAND-BASED 2D PHARMACOPHORE GENERATION FOR H+/K+ ATPASE INHIBITORS

scholarly journals Solution Structures and Dynamic Assembly of the 24-Meric Plasmodial Pdx1–Pdx2 Complex

2020 ◽  
Vol 21 (17) ◽  
pp. 5971
Author(s):  
Najeeb Ullah ◽  
Hina Andaleeb ◽  
Celestin Nzanzu Mudogo ◽  
Sven Falke ◽  
Christian Betzel ◽  
...  
Keyword(s):  
Drug Targets ◽  
Pyridoxal Phosphate ◽  
Plasmodium Species ◽  
Resistance Mechanisms ◽  
New Drugs ◽  
Enzyme Complex ◽  
Solution Structures ◽  
Dynamic Assembly ◽  
Bioanalytical Techniques ◽  
Initial Drug

Plasmodium species are protozoan parasites causing the deadly malaria disease. They have developed effective resistance mechanisms against most antimalarial medication, causing an urgent need to identify new antimalarial drug targets. Ideally, new drugs would be generated to specifically target the parasite with minimal or no toxicity to humans, requiring these drug targets to be distinctly different from the host’s metabolic processes or even absent in the host. In this context, the essential presence of vitamin B6 biosynthesis enzymes in Plasmodium, the pyridoxal phosphate (PLP) biosynthesis enzyme complex, and its absence in humans is recognized as a potential drug target. To characterize the PLP enzyme complex in terms of initial drug discovery investigations, we performed structural analysis of the Plasmodium vivax PLP synthase domain (Pdx1), glutaminase domain (Pdx2), and Pdx1–Pdx2 (Pdx) complex (PLP synthase complex) by utilizing complementary bioanalytical techniques, such as dynamic light scattering (DLS), X-ray solution scattering (SAXS), and electron microscopy (EM). Our investigations revealed a dodecameric Pdx1 and a monodispersed Pdx complex. Pdx2 was identified in monomeric and in different oligomeric states in solution. Interestingly, mixing oligomeric and polydisperse Pdx2 with dodecameric monodisperse Pdx1 resulted in a monodispersed Pdx complex. SAXS measurements revealed the low-resolution dodecameric structure of Pdx1, different oligomeric structures for Pdx2, and a ring-shaped dodecameric Pdx1 decorated with Pdx2, forming a heteromeric 24-meric Pdx complex.

scholarly journals Understanding the yeast host cell response to recombinant membrane protein production

2011 ◽  
Vol 39 (3) ◽  
pp. 719-723 ◽  
Author(s):  
Zharain Bawa ◽  
Charlotte E. Bland ◽  
Nicklas Bonander ◽  
Nagamani Bora ◽  
Stephanie P. Cartwright ◽  
...  
Keyword(s):  
Membrane Proteins ◽  
Membrane Protein ◽  
Drug Targets ◽  
Large Scale ◽  
Protein Production ◽  
Molecular Mechanisms ◽  
New Drugs ◽  
Host Cells ◽  
Host Cell Response ◽  
Wide Range

Membrane proteins are drug targets for a wide range of diseases. Having access to appropriate samples for further research underpins the pharmaceutical industry's strategy for developing new drugs. This is typically achieved by synthesizing a protein of interest in host cells that can be cultured on a large scale, allowing the isolation of the pure protein in quantities much higher than those found in the protein's native source. Yeast is a popular host as it is a eukaryote with similar synthetic machinery to that of the native human source cells of many proteins of interest, while also being quick, easy and cheap to grow and process. Even in these cells, the production of human membrane proteins can be plagued by low functional yields; we wish to understand why. We have identified molecular mechanisms and culture parameters underpinning high yields and have consolidated our findings to engineer improved yeast host strains. By relieving the bottlenecks to recombinant membrane protein production in yeast, we aim to contribute to the drug discovery pipeline, while providing insight into translational processes.

scholarly journals The KH domain facilitates the substrate specificity and unwinding processivity of DDX43 helicase

2020 ◽  
pp. jbc.RA120.015824
Author(s):  
Manisha Yadav ◽  
Ravi Shankar Singh ◽  
Daniel Hogan ◽  
Venkatasubramanian Vidhyasagar ◽  
Shizhuo Yang ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Mutational Analysis ◽  
Sequence Specificity ◽  
Nucleic Acid Binding ◽  
Mobility Shift ◽  
Dead Box ◽  
Kh Domain ◽  
Mobility Shift Assay ◽  
Exponential Enrichment ◽  
Binding Sequence

The K-homology (KH) domain is a nucleic acid binding domain present in many proteins. Recently we found that the DEAD-box helicase DDX43 contains a KH domain in its N-terminus; however, its function remains unknown. Here, we purified recombinant DDX43 KH domain protein and found that it prefers binding single-stranded (ss)DNA and ssRNA. Electrophoretic mobility shift assay (EMSA) and nuclear magnetic resonance (NMR) revealed that the KH domain favors pyrimidines over purines. Mutational analysis showed that the GXXG-loop in the KH domain is involved in pyrimidine binding. Moreover, we found that an alanine residue adjacent to the GXXG loop is critical for binding. SELEX (systematic evolution of ligands by exponential enrichment), chromatin immunoprecipitation (ChIP)-seq, and crosslinking immunoprecipitation (CLIP)-seq showed that the KH domain binds C/T rich DNA and U rich RNA. Bioinformatics analysis suggested that the KH domain prefers to bind promoters. Using 15N-HSQC NMR, the optimal binding sequence was identified as TTGT. Finally, we found that the full-length DDX43 helicase prefers DNA or RNA substrates with TTGT or UUGU single strand tails, and that the KH domain is critically important for sequence specificity and unwinding processivity. Collectively, our results demonstrated that the KH domain facilitates the substrate specificity and processivity of the DDX43 helicase.

scholarly journals The crystal structure of mycobacterial epoxide hydrolase A

2020 ◽  
Vol 10 (1) ◽  
Author(s):  
Eike C. Schulz ◽  
Sara R. Henderson ◽  
Boris Illarionov ◽  
Thomas Crosskey ◽  
Stacey M. Southall ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Substrate Specificity ◽  
Drug Targets ◽  
Epoxide Hydrolase ◽  
Sequence Similarity ◽  
Structural Similarity ◽  
High Sequence Similarity ◽  
High Structural Similarity ◽  
Potential Drug Targets ◽  
Insight Into

Abstract The human pathogen Mycobacterium tuberculosis is the causative agent of tuberculosis resulting in over 1 million fatalities every year, despite decades of research into the development of new anti-TB compounds. Unlike most other organisms M. tuberculosis has six putative genes for epoxide hydrolases (EH) of the α/β-hydrolase family with little known about their individual substrates, suggesting functional significance for these genes to the organism. Due to their role in detoxification, M. tuberculosis EH’s have been identified as potential drug targets. Here, we demonstrate epoxide hydrolase activity of M. thermoresistibile epoxide hydrolase A (Mth-EphA) and report its crystal structure in complex with the inhibitor 1,3-diphenylurea at 2.0 Å resolution. Mth-EphA displays high sequence similarity to its orthologue from M. tuberculosis and generally high structural similarity to α/β-hydrolase EHs. The structure of the inhibitor bound complex reveals the geometry of the catalytic residues and the conformation of the inhibitor. Comparison to other EHs from mycobacteria allows insight into the active site plasticity with respect to substrate specificity. We speculate that mycobacterial EHs may have a narrow substrate specificity providing a potential explanation for the genetic repertoire of epoxide hydrolase genes in M. tuberculosis.

scholarly journals Stress-Responsive Systems Set Specific Limits to the Overproduction of Membrane Proteins in Bacillus subtilis

2009 ◽  
Vol 75 (23) ◽  
pp. 7356-7364 ◽  
Author(s):  
Jessica C. Zweers ◽  
Thomas Wiegert ◽  
Jan Maarten van Dijl
Keyword(s):  
Bacillus Subtilis ◽  
Membrane Proteins ◽  
Membrane Protein ◽  
Drug Targets ◽  
Protein Production ◽  
Cell Envelope ◽  
Regulatory System ◽  
Interesting Candidate ◽  
High Level ◽  
And Function

ABSTRACT Essential membrane proteins are generally recognized as relevant potential drug targets due to their exposed localization in the cell envelope. Unfortunately, high-level production of membrane proteins for functional and structural analyses is often problematic. This is mainly due to their high overall hydrophobicity. To develop new concepts for membrane protein overproduction, we investigated whether the biogenesis of overproduced membrane proteins is affected by stress response-related proteolytic systems in the membrane. For this purpose, the well-established expression host Bacillus subtilis was used to overproduce eight essential membrane proteins from B. subtilis and Staphylococcus aureus. The results show that the σW regulon (responding to cell envelope perturbations) and the CssRS two-component regulatory system (responding to unfolded exported proteins) set critical limits to membrane protein production in large quantities. The identified sigW or cssRS mutant B. subtilis strains with significantly improved capacity for membrane protein production are interesting candidate expression hosts for fundamental research and biotechnological applications. Importantly, our results pinpoint the interdependent expression and function of membrane-associated proteases as key parameters in bacterial membrane protein production.

scholarly journals Loop 3 of Fungal Endoglucanases of Glycoside Hydrolase Family 12 Modulates Catalytic Efficiency

2016 ◽  
Vol 83 (6) ◽  
Author(s):  
Hong Yang ◽  
Pengjun Shi ◽  
Yun Liu ◽  
Wei Xia ◽  
Xiaoyu Wang ◽  
...  
Keyword(s):  
Substrate Specificity ◽  
Glycoside Hydrolase ◽  
Turnover Rate ◽  
Catalytic Efficiency ◽  
Glycoside Hydrolase Family ◽  
Multiple Sequence ◽  
Content Type ◽  
Hydrogen Bond Interactions ◽  
Wide Range ◽  
Hydrogen Network

ABSTRACT Glycoside hydrolase (GH) family 12 comprises enzymes with a wide range of activities critical for the degradation of lignocellulose. However, the important roles of the loop regions of GH12 enzymes in substrate specificity and catalytic efficiency remain poorly understood. This study examined how the loop 3 region affects the enzymatic properties of GH12 glucanases using NfEG12A from Neosartorya fischeri P1 and EG (PDB 1KS4 ) from Aspergillus niger. Acidophilic and thermophilic NfEG12A had the highest catalytic efficiency (k cat/Km , 3,001 and 263 ml/mg/s toward lichenin and carboxymethyl cellulose sodium [CMC-Na], respectively) known so far. Based on the multiple-sequence alignment and homology modeling, two specific sequences (FN and STTQA) were identified in the loop 3 region of GH12 endoglucanases from fungi. To determine their functions, these sequences were introduced into NfEG12A, or the counterpart sequence STTQA was removed from EG. These modifications had no effects on the optimal pH and temperature or substrate specificity but changed the catalytic efficiency (k cat/Km ) of these enzymes (in descending order, NfEG12A [100%], NfEG12A-FN [140%], and NfEG12A-STTQA [190%]; EG [100%] and EGΔSTTQA [41%]). Molecular docking and dynamic simulation analyses revealed that the longer loop 3 in GH12 may strengthen the hydrogen-bond interactions between the substrate and protein, thereby increasing the turnover rate (k cat). This study provides a new insight to understand the vital roles of loop 3 for GH12 endoglucanases in catalysis. IMPORTANCE Loop structures play critical roles in the substrate specificity and catalytic hydrolysis of GH12 enzymes. Three typical loops exist in these enzymes. Loops 1 and 2 are recognized as the catalytic loops and are closely related to the substrate specificity and catalytic efficiency. Loop 3 locates in the −1 or +1 subsite and varies a lot in amino acid composition, which may play a role in catalysis. In this study, two GH12 glucanases, NfEG12A and EG, which were mutated by introducing or deleting partial loop 3 sequences FN and/or STTQA, were selected to identify the function of loop 3. It revealed that the longer loop 3 of GH12 glucanases may strengthen the hydrogen network interactions between the substrate and protein, consequently increasing the turnover rate (k cat). This study proposes a strategy to increase the catalytic efficiency of GH12 glucanases by improving the hydrogen network between substrates and catalytic loops.

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