Publications by authors named "Surasak Chunsrivirot"

Brought about by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), coronavirus disease (COVID-19) pandemic has resulted in large numbers of worldwide deaths and cases. Several SARS-CoV-2 variants have evolved, and Omicron (B.1.

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  • Intelectins are immune lectins found in chordates, with XCGL-1 being the first identified, crucial for fertilization membrane development.
  • Researchers studied XCGL-1's biochemical properties, revealing its four-lobed structure and the significance of cysteines for disulfide bond formation.
  • XCGL-1 binds galactose-containing carbohydrates with high affinity and the findings could lead to new applications in glycobiology.
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α-L-rhamnosidase catalyzes hydrolysis of the terminal α-L-rhamnose from various natural rhamnoglycosides, including naringin and hesperidin, and has various applications such as debittering of citrus juices in the food industry and flavonoid derhamnosylation in the pharmaceutical industry. However, its activity is lost at high temperatures, limiting its usage. To improve Lactobacillus acidophilus α-L-rhamnosidase stability, we employed molecular dynamics (MD) to identify a highly flexible region, as evaluated by its root mean square fluctuation (RMSF) value, and computational protein design (Rosetta) to increase rigidity and favorable interactions of residues in highly flexible regions.

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  • Intelectins are immune proteins found in chordates, including fish, that are activated during infections; however, their specific functions and properties in fish are not fully understood.
  • The study focuses on zebrafish intelectin-2 (DrIntL-2), which is mainly found in the gastrointestinal tract, revealing its structure and binding characteristics with bacteria.
  • Findings suggest DrIntL-2 could play a vital role in fish immune response and has potential applications in detecting and identifying harmful bacteria, benefiting the aquaculture industry.
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  • A β-mannanase (Man26HM7) from Bacillus subtilis HM7 was cloned and expressed in E. coli, showing optimal activity at pH 6.0 and 50 °C.
  • This enzyme exhibits strong surfactant stability, maintaining 70% activity in SDS and over 90% in Triton X-100 and Tween 80.
  • Research indicates residue 238 is key for SDS tolerance, and modifications to this site in a similar enzyme improved its stability, pointing to potential applications in detergents and enzyme engineering for better surfactant performance.
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SARS-CoV-2 is responsible for COVID-19 pandemic, causing large numbers of cases and deaths. It initiates entry into human cells by binding to the peptidase domain of angiotensin-converting enzyme 2 (ACE2) receptor via its receptor binding domain of S1 subunit of spike protein (SARS-CoV-2-RBD). Employing neutralizing antibodies to prevent binding between SARS-CoV-2-RBD and ACE2 is an effective COVID-19 therapeutic solution.

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  • Pfs25 is a key candidate for malaria transmission-blocking vaccines, but its genetic diversity has not been thoroughly studied in various endemic populations.
  • A comprehensive analysis of 307 Pfs25 sequences revealed 11 unique haplotypes, with two dominant ones (H1 and H2) making up the majority and showing region-specific prevalence.
  • The study identified specific single-nucleotide polymorphisms (SNPs) contributing to this diversity, with implications for the effectiveness of vaccines across different geographical regions.
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SARS-CoV-2 is coronavirus causing COVID-19 pandemic. To enter human cells, receptor binding domain of S1 subunit of SARS-CoV-2 (SARS-CoV-2-RBD) binds to peptidase domain (PD) of angiotensin-converting enzyme 2 (ACE2) receptor. Employing peptides to inhibit binding between SARS-CoV-2-RBD and ACE2-PD is a therapeutic solution for COVID-19.

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  • Levan-type fructooligosaccharides (LFOs) and levan are promising for use in prebiotics, skincare, and cancer treatment, but the levansucrase enzyme (OPL) has low thermostability.
  • Research utilized molecular dynamics to identify a flexible region in OPL and used protein design techniques to create 14 mutants that were more stable at high temperatures.
  • Among these, K296E, G309S, and A310W showed increased stability due to improved hydrogen bonding, making them ideal candidates for more effective LFO production.
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SARS-CoV-2 is the novel coronavirus causing the COVID-19 pandemic. To enter human cells, the receptor-binding domain (RBD) of the S1 subunit of SARS-CoV-2 (SARS-CoV-2-RBD) initially binds to the peptidase domain of angiotensin-converting enzyme 2 receptor (ACE2-PD). Using peptides to inhibit SARS-CoV-2-RBD binding to ACE2 is a potential therapeutic solution for COVID-19.

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Lipopolysaccharide (LPS) is a crucial component in the outer membrane of Gram-negative bacteria that contributes to both pathogenicity as well as immunity against pathogenic bacteria. Typical LPS contains GlcN disaccharide as the core of lipid A. However, some bacteria such as and contain GlcN3N in lipid A instead.

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  • Inulosucrase is an enzyme that creates fructooligosaccharides from sucrose, and calcium is crucial for its activity and stability.
  • Mutations in specific calcium-binding sites of the enzyme reduced its stability and activity, affecting the types of fructooligosaccharides produced.
  • Experiments showed that altering one key calcium-binding residue significantly influenced the length of the fructooligosaccharide chains generated by the enzyme.
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Levansucrase catalyzes production of levan and levan-type fructooligosaccharides (LFOs) with potential applications in food and pharmaceutical industries such as prebiotics and anti-tumor agents. Previous study found that Y246S mutant of Bacillus licheniformis RN-01 levansucrase (oligosaccharide producing levansucrase, OPL) could effectively produce LFOs but its thermostability is limited at high temperature. In this study, molecular dynamics (MD) and computational protein design were used to create mutants with higher thermostability than OPL by rigidifying highly flexible residues on enzyme surface.

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European honeybee, Apis mellifera, produces α-glucosidase (HBGase) that catalyzes the cleavage of an α-glycosidic bond of the non-reducing end of polysaccharides and has potential applications for malt hydrolysis in brewing industry. Characterized by their substrate specificities, HBGases have three isoforms including HBGase II, which prefers maltose to sucrose as a substrate. Previous study found that the catalytic efficiency of maltose hydrolysis of N226P mutant of HBGase II was higher than that of the wild type (WT), and the catalytic efficiency of maltose hydrolysis of WT was higher than those of H227Y and N226P-H227Y mutants.

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Levansucrase (LS) from Gram-positive bacteria generally produces a large quantity of levan polymer, a polyfructose with glucose at the end (GF) but a small quantity of levan-type fructooligosaccharides (LFOs). The properties of levan and LFOs depend on their chain lengths, thereby determining their potential applications in food and pharmaceutical industries such as prebiotics and anti-tumor agents. Therefore, an ability to redesign and engineer the active site of levansucrase for synthesis of products with desired degree of polymerization (DP) is very beneficial.

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  • Fructooligosaccharides (FOSs) are prebiotics useful in various industries, and inulosucrase can be engineered to synthesize different FOS chain lengths from sucrose.
  • Three engineered variants of inulosucrase (R483F, R483Y, R483W) showed improved binding to a specific substrate, leading to higher production of shorter chain FOSs (GF5) compared to the wild type.
  • Even though the engineered variants displayed reduced overall catalytic activity, they could still achieve FOS synthesis yields of up to 73% from the substrate, confirming the effectiveness of the modifications.
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  • Levan and its oligosaccharides, produced by levansucrase, show promise for use in the food and pharmaceutical industries for functions like prebiotics and anti-tumor agents.
  • Mutations in Bacillus licheniformis RN-01 levansucrase (specifically N251A and N251Y) enable the production of short-chain oligosaccharides (up to GF3), but hinder the formation of long-chain levan due to decreased binding affinity for GF3.
  • Molecular dynamics analysis reveals that these mutations do not significantly affect GF2 binding but significantly disrupt GF3 binding, highlighting the role of Arg255 in the levansucrase active site and offering insights into the mechanisms of oligosaccharide production
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Levan has various potential applications in the pharmaceutical and food industries, such as cholesterol-lowering agents and prebiotics, due to its beneficial properties, which depend on its length and branching degree. A previous study also found that the branching degree of levan affected anti-tumor activities against SNU-1 and HepG2 tumor cell lines. Despite its promising potential, the properties of levans with different branching degrees are not well understood at the molecular level.

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Honey from the European honeybee, Apis mellifera, is produced by α-glucosidases (HBGases) and is widely used in food, pharmaceutical, and cosmetic industries. Categorized by their substrate specificities, HBGases have three isoforms: HBGase I, II and III. Previous experimental investigations showed that wild-type HBGase III from Apis mellifera (WT) preferred sucrose to maltose as a substrate, while the Y227H mutant (MT) preferred maltose to sucrose.

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Advanced oral squamous cell carcinoma (OSCC) is typically aggressive and closely correlated with disease recurrence and poor survival. Multidrug resistance (MDR) is the most critical problem leading to therapeutic failure. Investigation of novel anticancer candidates targeting multidrug-resistant OSCC cells may provide a basis for developing effective strategies for OSCC treatment.

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Background: Levan and levan-type fructo-oligosaccharides (LFOs) have various potential applications in pharmaceutical and food industries due to their beneficial properties such as their low intrinsic viscosity and high water solubility. Previous studies showed that they exhibited prebiotic effects, anti-inflammatory and anti-tumor activities against Sarcoma-180 tumor cells of human. Despite their various potential applications, the structural and molecular properties of LFOs of various chain lengths are not well understood.

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Human papillomavirus 16 (HPV 16) is a DNA virus that is capable of infecting humans and causing cervical cancer. HPV16 E2 plays an important role in viral gene regulation. This work aims to predict the binding conformations and interactions between the dodecapeptides and HPV16 E2 as well as to design novel peptide inhibitors that are capable of binding to HPV16 E2 and disrupt the transcriptional regulator E1-E2 complex formation, using computational protein design techniques.

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