• Asian Pacific Journal of Cancer Prevention
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• v.15 no.6
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• pp.2747-2751
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• 2014

Background: DNA repair pathways play a crucial role in maintaining the human genome. Previous studies associated DNA repair gene polymorphisms (XPD Lys751Gln, XRCC1 Arg280His and XRCC1 Arg399Gln) with nasopharyngeal carcinoma. These non-synonymous polymorphisms may alter DNA repair capacity and thus increase or decrease susceptibility. The present study aimed to determine the genotype distribution of XPD codon 751, XRCC1 codon 280 and codon 399 polymorphisms and haplotype associations among NPC cases and controls in the Malaysian population. Materials and Methods: We selected 157 NPC cases and 136 controls from two hospitals in Kuala Lumpur, Malaysia for this study. The polymorphisms studied were genotyped by PCR-RFLP assay and allele and genotype frequenci es, haplotype and linkage disequilibrium were determined using SNPstat software. Results: For the XPD Lys751Gln polymorphism, the frequency of the Lys allele was higher in cases than in controls (94.5% versus 85.0%). For the XRCC1 Arg280His polymorphism, the frequency of Arg allele was 90.0% and 89.0% in cases and controls, respectively and for XRCC1 Arg399Gln the frequency of the Arg allele was 72.0% and 72.8% in cases and controls respectively. All three polymorphisms were in linkage disequilibrium. The odds ratio from haplotype analysis for these three polymorphisms and their association with NPC was 1.93 (95%CI: 0.90-4.16) for haplotype CGC vs AGC allele combinations. The global haplotypte association with NPC gave a p-value of 0.054. Conclusions: Our study provides an estimate of allele and genotype frequencies of XRCC1Arg280His, XRCC1 Arg399Gln and XPD Lys751Gln polymorphisms in the Malaysian population and showed no association with nasopharyngeal cancer.

• Journal of Integrative Natural Science
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• v.1 no.1
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• pp.47-53
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• 2008

In a previous study, we showed that Cecropin A (1-8)-Magainin 2 (1-12) hybrid peptide (CA-MA)'s analogue, Anal P5, exhibit broad-spectrum antimicrobial activity. Anal P5, designed by flexible region (positions 9, 10)-substitution, Lys- (positions 4, 8, 14, 15) and Leu- (positions 5, 6, 12, 13, 16, 17, 20) substitutions, showed an enhanced antimicrobial and antitumor activity without hemolysis. The primary objective of the present study was to gain insight into the relevant mechanisms of antimicrobial activities of Anal P5 by using flow cytometric analysis. Anal P5 exhibits strong antifungal activity in a salt concentration independent manner. In addition, Anal P5 causes significant morphological alterations of the bacterial surfaces as shown by scanning electron microscopy, supporting its antibacterial activity. Its potent antibiotic activity suggests that Anal P5 is an excellent candidate as a lead compound for the development of novel antibiotic agents.

• BMB Reports
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• v.30 no.6
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• pp.397-402
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• 1997

A thiol-specific spin label was attached to cysteine-102 of yeast cytochrome c and electron paramagnetic resonance (EPR) spectra were measured as a function of added cytochrome c oxidase concentration. The intensity decreased due to line broadening as cytochrome c formed a complex with cytochrome c oxidase and reached a minimum when the ratio of cytochrome c to cytochrome c oxidase became one. Replacement of either Lys-72 or Lys-87 of cytochrome c by Glu did not result in a significant change in binding affinity. Interestingly the K72E mutant, unlike K87E, had a much lower rate of electron transfer than the wild type. These results indicate that many positively charged residues as a group participate in complex formation but Lys-72 might be important for cytochrome c to be locked in an orientation for an efficient electron transfer. A stoichiometry of 1 was also confirmed by optical absorption of the cytochrome c-cytochrome c oxidase complex which had been run through a gel chromatography cloumn to remove unbound cytochrome c. The EPR spectrum of this 1:1 complex, however, was a mixture of two components. This explains a biphasic kinetics for a single binding site on cytochrome c oxidase without invoking conformational transition.

• Molecules and Cells
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• v.22 no.3
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• pp.328-335
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• 2006

Imperatoxin A ($IpTx_a$), a 3.7 kDa peptide from the African scorpion Pandinus imperator, is an agonist of the skeletal muscle ryanodine receptor (RyR1). In order to study the structure of the toxin and its effect on RyR1, $IpTx_a$ cDNA was PCR-amplified using 3 pairs of primers, and the toxin was expressed in E. coli. The toxin was further purified by chromatography, and various point mutants in which basic amino acids were substituted by alanine were prepared by site-directed mutagenesis. Studies of single channel properties by the planar lipid bilayer method showed that the recombinant $IpTx_a$ was identical to the synthetic $IpTx_a$ with respect to high-performance liquid chromatography mobility, amino acid composition and specific effects on RyR1. Mutations of certain basic amino acids ($Lys^{19}$, $Arg^{23}$, and $Arg^{33}$) dramatically reduced the capacity of the peptide to activate RyRs. A subconductance state predominated when $Lys^8$ was substituted with alanine. These results suggest that some basic amino acid residues in $IpTx_a$ are important for activation of RyR1, and that $Lys^8$ plays an important role in regulating the gating mode of RyR1.

• Korean Journal of Environmental Biology
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• v.21 no.1
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• pp.77-85
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• 2003

We have examined the 16S-23S rRNA intergenic spacer regions (ISR) of Vibrio fluvialis. ISRs were PCR amplified, cloned into a plasmid vector and then sequenced. As results of ISR nucleotide sequence analysis, total of 6 clones were isolated depending on the size. The clones were different in both the number and the composition of the tRNA genes, and were designated ISR-A, ISR-E, ISR-El, ISR-lA, ISR-EKV, ISR-EKAV. ISR-A contains $tRNA^{Ala}$; ISR-lA, $tRNA^{Ile}$-$tRNA^{Ala}$; ISR-EKV, $tRNA^{GIu}$-$tRNA^{Lys}$-$tRNA^{Val}$;ISE-EKAV, $tRNA^{GIu}$-$tRNA^{Lys}$-$tRNA^{Ala}$-$tRNA^{Val}$; ISR -E and E1, $tRNA^{GIu}$ clusters. ISR-EKV was shown to be a minor type out of the six ISR types and showed a very limited homology between ISR-EKV from V, fluvialis and ISRa from other Vibrio species. Therefore ISR-EKV sequence was used to design species-specific primers to detect V, fiuvialis from other Vibrio species by PCR reaction. The specificity of the primers was examined using genomic DNA of other Vibrios as templates for PCR reaction. The result showed that PCR can be a useful method to detect V. fluvialis among Vibrio species in a single PCR reaction.

• Bulletin of the Korean Chemical Society
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• v.30 no.6
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• pp.1360-1364
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• 2009

The bacterium Sphingomonas chungbukensis DJ77 produces the extracellular polysaccharide gellan in high yield. Gellan produced by this bacterium is widely used as a gelling agent, and the enzyme UDP-glucose pyrophosphorylase (UGP) is thought to play a key role in the gellan biosynthetic pathway. The UGP gene has been successfully cloned and over-expressed in E. coli. The expressed enzyme was purified with a molecular weight of approximately 32 kDa, as determined by a SDS-polyacrylamide gel, but the enzyme appears as ca. 63 kDa on a native gel, suggesting that the enzyme is present in a homodimer. Kinetic analysis of UDP-glucose for UGP indicates $K_m$ = 1.14 mM and $V_{max}$ = 10.09 mM/min/mg at pH 8.0, which was determined to be the optimal pH for UGP catalytic activity. Amino acid sequence alignment against other bacteria suggests that the UGP contains two conserved domains: An activator binding site and a glucose-1-phosphate binding site. Site-directed mutagenesis of Lys194, located within the glucose-1-phosphate binding site, indicates that substitution of the charge-reversible residue Asp for Lys194 dramatically impairs the UGP activity, supporting the hypothesis that Lys194 plays a critical role in the catalysis.

• 한국생물공학회:학술대회논문집
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• 2003.10a
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• pp.630-633
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• 2003

The mussel adhesive protein Mefp-1 is a natural, strong and durable adhesive that is stable under corrosive, saline conditions. Mefp-1 is found in the marine mussel Mytilus edulis and it has a molecular weight of ca. 130,000. The primary structure is mainly composed of repeating decapetides: Ala-Lys-Pro -Ser-Tyr Hyp-Hyp-Thr-DOPA-Lys. To elucidate the mechanism by which Mefp-1 bonds to metal surfaces, we have used surface-enhanced Raman spectroscopy to study the interactions of peptides related to the Mefp-1 decapeptide repeat with gold surfaces. We have concluded that the tyrosine residue and the carboxyl terminus interact strongly with the gold surface, and that proline and hydroxyproline constrain the conformations of the peptides, thereby limiting the types of possible interactions of the functional groups with the gold surface.

• Microbiology and Biotechnology Letters
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• v.16 no.6
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• pp.536-539
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• 1988

A mutant of Bacillus subtilis with a defective cdd gene encoding deoxycytidine-cytidine deaminase (EC 3.5.4.5) has been characterized genetically. The genetic lesion, cdd, causing the altered deoxycytidine-cytidine deaminase was mapped at 225 min on the linkage map of B. subtilis by AR9 transduction, Transductional analysis of the cdd region established the gene order in clockwise as trp-lys-cdd-aroD. The cdd gene was linked 72% with the aroD and 20% with the lys.

• Molecules and Cells
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• v.41 no.4
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• pp.301-310
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• 2018

LysR-type transcriptional regulators (LTTRs) contain an N-terminal DNA binding domain (DBD) and a C-terminal regulatory domain (RD). Typically, LTTRs function as homotetramers. VV2_1132 was identified in Vibrio vulnificus as an LTTR that is a homologue of HypT (also known as YjiE or QseD) in Escherichia coli. In this study, we determined the crystal structure of full-length VV2_1132 at a resolution of $2.2{\AA}$, thereby revealing a novel combination of the domains in the tetrameric assembly. Only one DBD dimer in the tetramer can bind to DNA, because the DNA binding motifs of the other DBD dimer are completely buried in the tetrameric assembly. Structural and functional analyses of VV2_1132 suggest that it might not perform the same role as E. coli HypT, indicating that further study is required to elucidate the function of this gene in V. vulnificus. The unique structure of VV2_1132 extends our knowledge of LTTR function and mechanisms of action.

• The Korean Journal of Mycology
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• v.32 no.2
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• pp.119-124
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• 2004

Metalloenzyme was purified from the fruiting bodies of Tricholoma sejunctum. MALDI-TOF and ICP/MS analyses revealed that the enzyme had a molecular weight of 18788.25 and includes $Zn^{2+}$ ion. The N-terminal amino acid sequence of the enzyme was Ala-Thr-Tyr-Lys-Ile-X-Ser-Ala-Thr-His-Gln-X-X-Leu-Val. The activity of the enzyme was inhibited by EDTA and 1,10-phenanthroline, indicating that the enzyme was a metalloprotease. No inhibition was found with E-64 and pepstatin. It has broad substrate specificity for synthetic peptides. The enzyme was stable up to $40^{\circ}C$. The activity of the enzyme was increased by $Zn^{2+}$ and $Co^{2+}$, while it was totally inhibited by $Hg^{2+}$. The enzyme hydrolyzes $A{\alpha}$ subunit of human fibrinogen but did not show any reactivity for $B{\beta}$ and ${\gamma}$ form of human fibrinogen.