• Bulletin of the Korean Chemical Society
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• v.26 no.1
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• pp.151-156
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• 2005

The conformational dynamics of heme pocket, a small vacant site near the binding site of heme proteins -myoglobin (Mb) and hemoglobin (Hb), was investigated after photolysis of carbon monoxide from MbCO and HbCO in D$_2$O solution at 283 K by probing time-resolved vibrational spectra of photolyzed CO. Two absorption bands, arising from CO in the heme pocket, evolve nonexponentially in time. The band at higher energy side blue shifts and broadens with time and the one at lower energy side narrows significantly with a negligible shift. These spectral evolutions are induced by protein conformational changes following photolysis that modify structure and electric field of heme pocket, and ligand dynamics in it. The conformational changes affecting the spectrum of photolyzed CO in heme pocket likely modulates ligand-binding activity.

• Bulletin of the Korean Chemical Society
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• v.28 no.2
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• pp.339-342
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• 2007

• Bulletin of the Korean Chemical Society
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• v.27 no.11
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• pp.1825-1831
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• 2006

The influence of solvent viscosity on conformational dynamics of the heme-pocket, a small vacant site near the binding site of myoglobin (Mb) and hemoglobin (Hb), and playing a functionally important role by serving as a station in ligand binding and escape, was studied by probing time-resolved vibrational spectra of CO photodissociated from MbCO and HbCO in $D_2O$, 75 wt% glycerol/$D_2O$, and trehalose at 283 K. Two absorption bands ($B_1$ and $B_2$) of the sample in viscous solvents, arising from CO in the heme pocket, are very similar to those in $D_2O$. Two bands in Mb and Hb under all three solvents exhibit very similar nonexponential spectral evolution ($B_1$ band; blue shifting and broadening, $B_2$ band; narrowing with a negligible shifting), suggesting that in the present experimental time window of 100 ps, the extents of the spectral shift and narrowing is much influenced neither by the viscosity of solvent nor by the quaternary contact of Hb. Spectral evolution can be described by a biexponential function with a fast universal time constant of 0.52 ps and a slow time constant ranging from 13 to 32 ps. For both proteins in all three solvents majority of spectral evolution occurs with the fast universal time constant. The magnitude of the slow rate in the spectral shift of B1 band decreases with increasing solvent viscosity, indicating that it is influenced by global conformational change which is retarded in viscous solvent, thereby serve as a reporter of global conformational change of heme proteins after deligation.

• Journal of Dental Rehabilitation and Applied Science
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• v.37 no.1
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• pp.31-38
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• 2021

Purpose: The purpose of this study was to investigate effect of heme on periodontopathogens. Materials and Methods: The experiment was performed using 7 types of anaerobic bacteria present in the periodontal pocket. The bacteria were cultured using suitable medium in an anaerobic condition with or without hemin, and the growth of the bacteria was measured every 6 hours by a spectrophotometer. Results: the growth of Porphyromonas gingivalis was different only by the presence or absence of hemin. The growth of other periodontopathogens except Treponema denticola was different in a hemin concentration-dependent manner. The growth of T. denticola was interfered by hemin. Conclusion: Heme may be a factor that leads dysbiosis in the microbial ecosystem of the subgingival plaque and thereby promote a periodontitis-causing environment.

• Journal of Microbiology and Biotechnology
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• v.8 no.3
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• pp.295-299
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• 1998

Oligonucleotide primers were designed and successfully applied to amplify DNA fragments of P450 hydroxylase genes from actinomycetes which produce a large variety of medically important metabolites. Primers were designed based on several regions of strong similarities in amino acid sequence of P450 hydroxylases from a variety of actinomycetes, primarily in the regions of an oxygen binding site and a heme ligand pocket. These primers were used to amplify DNA fragments from seven different actinomycetes species producing a variety of different compounds. The deduced amino acid sequences of the isolated fragments revealed significant similarities to known P450 hydroxylase including the product of the suaC or subC genes from Streptomyces griseolus that is capable of metabolizing a number of sulfonylurea herbicides, and to the product of the $P450_{sca2}$ from S. carbophilus that produces a specific HMG-CoA reductase inhibitor. This method should help researchers in cloning the P450 hydroxylase genes involved in the biosynthesis of useful compounds.

• KSBB Journal
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• v.19 no.4
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• pp.308-314
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• 2004

A degenerate set of PCR primers based on two conserved regions (heme binding region and oxygen ligand pocket) were designed and successfully applied to amplify DNA fragments of cytochrome P450 hydroxylase (CYP) genes from a rare actinomycetes, S. benihana. The PCR amplified products were employed as a DNA probe to clone the entire CYP genes from S. benihana genomic library. Five different CYP-positive cosmids were isolated by colony hybridization as well as PCR confirmation. The complete nucleotide sequencing of five different CYP genes revealed that each unique CYP showed a significant amino acid homology to previously-known CYP genes involved in streptomycetes secondary metabolism. In addition, four CYP genes (CYP502, CYP503, CYP504, CYP506) were found to be linked to ferredoxin genes in the chromosome, and the CYP503 gene showed the high degree of amino acid similarity to the previously well-characterized CYP105 family in streptomycetes.

• Journal of Microbiology
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• v.40 no.3
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• pp.211-218
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• 2002

A 4.8-kb DNA fragment encoding the P-450 type hydroxylase and ferredoxin genes was cloned from Pseudonocardia autotrophica IFO 12743 that can convert vitamin D$\_$3/ into its hydroxylated active forms. In order to isolate the P-450 gene cluster in this organism, we designed PCR primers on the basis of the regions of an oxygen binding site and a heme ligand pocket that are general characteristics of the P-450 hydroxylase. Sequencing analysis of the BamHI fragment revealed the presence of four complete and one incomplete ORFs, named PauA, PauB, PauC, and PauD, respectively. As a result of computer-based analyses, PauA and PauB have homology with enoyl-CoA hydratase from several organisms and the positive regulators belonging to the tetR family, respectively. PauC and PauD show similarity with SuaB/C proteins and ferredoxins, respectively, which are composed of P-450 monooxygenase systems for metabolizing two sulfonylurea herbicides in Streptomyces griseolus PauC shows the highest similarity with another CytP-450$\_$Sca2/ protein that is responsible for production of a specific HMG-CoA reductase inhibitor, pravastatin, in S. carbophilus. Cultures of Steptomyces lividans transformant, containing the P-450 gene cluster on the pWHM3 plasmid, was unable to convert vitamin D$\_$3/ to its hydroxylated forms.

• Journal of Microbiology and Biotechnology
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• v.20 no.3
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• pp.532-541
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• 2010

Peroxidase-like activity of Vitreoscilla hemoglobin (VHb) has been recently disclosed. To maximize such activity, two catalytically conserved residues (histidine and arginine) found in the distal pocket of peroxidases have successfully been introduced into that of the VHb. A 15-fold increase in catalytic constant ($k_{cat}$) was obtained in P54R variant,which was presumably attributable to the lower rigidity and higher hydrophilicity of the distal cavity arising from substitution of proline to arginine. None of the modifications altered the affinity towards either $H_2O_2$ or ABTS substrate. Spectroscopic studies revealed that VHb variants harboring the T29H mutation apparently demonstrated a spectral shift in both ferric and ferrous forms (406-408 to 411 nm, and 432 to 424-425 nm, respectively). All VHb proteins in the ferrous state had a $\lambda_{soret}$ peak at ~419 nm following the carbon monoxide (CO) binding. Expression of the P54R mutant mediated the downregulation of iron superoxide dismutase (FeSOD) as identified by two-dimensional gel electrophoresis (2-DE) and peptide mass fingerprinting (PMF). According to the high peroxidase activity of P54R, it could effectively eliminate autoxidation-derived $H_2O_2$, which is a cause of heme degradation and iron release. This decreased the iron availability and consequently reduced the formation of the $Fe^{2+}$-ferric uptake regulator protein ($Fe^{2+}$-Fur), an inducer of FeSOD expression.

• Molecules and Cells
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• v.39 no.3
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• pp.211-216
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• 2016

CYP107W1 from Streptomyces avermitilis is a cytochrome P450 enzyme involved in the biosynthesis of macrolide oligomycin A. A previous study reported that CYP107W1 regioselectively hydroxylated C12 of oligomycin C to produce oligomycin A, and the crystal structure of ligand free CYP107W1 was determined. Here, we analyzed the structural properties of the CYP107W1-oligomycin A complex and characterized the functional role of the Trp178 residue in CYP107W1. The crystal structure of the CYP107W1 complex with oligomycin A was determined at a resolution of $2.6{\AA}$. Oligomycin A is bound in the substrate access channel on the upper side of the prosthetic heme mainly by hydrophobic interactions. In particular, the Trp178 residue in the active site intercalates into the large macrolide ring, thereby guiding the substrate into the correct binding orientation for a productive P450 reaction. A Trp178 to Gly mutation resulted in the distortion of binding titration spectra with oligomycin A, whereas binding spectra with azoles were not affected. The Gly178 mutant's catalytic turnover number for the 12-hydroxylation reaction of oligomycin C was highly reduced. These results indicate that Trp178, located in the open pocket of the active site, may be a critical residue for the productive binding conformation of large macrolide substrates.

• Journal of Radiation Industry
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• v.2 no.3
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• pp.97-104
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• 2008

Cinnamate-4-hydroxylase (C4H) is a key enzyme of phenylpropanoid pathway, which leads a variety of secondary metabolites to participate in differentiation and protection of plant against environmental stresses. In this study, we isolated a full-length cDNA of the C4H gene from a black raspberry (Rubus occidentalis L.), using a reverse transcriptase-PCR and rapid amplification of the cDNA ends (RACE)-PCR. The full-length cDNA of the RocC4H gene contained a 1,515 bp open reading frame (ORF) encoding a 504 amino acid protein with a calculated molecular weight of about 57.9 kDa and an isoelectric point (pI) value of 9.1. The genomic DNA analysis revealed that RocC4H gene had three exons and two introns. By multiple sequence alignment, RocC4H protein was highly homologous with other plant C4Hs, and the cytochrome P450-featured motifs, such as the heme-binding domain, the T-containing binding pocket motif (AAIETT), the ERR triad, and the tetrapeptide (PPGP) hinge motif, were highly conserved. Southern blot analysis revealed that RocC4H is a single copy gene in R. occidentalis.