Pneumococcal LicC is a member of the nucleoside triphosphate transferase superfamily and catalyzes the transfer of a cytidine monophosphate from CTP to phosphocholine to form CDP-choline. The structures of apoLicC and the LicC⅐CDP-choline⅐Mg 2؉ ternary complex were determined, and the comparison of these structures reveals a significant conformational change driven by the multivalent coordination of Mg 2؉ . The key event is breaking the Glu 216 ⅐Arg 129 salt bridge, which triggers the coalescence of four individual ␤-strands into two extended ␤-sheets. These movements reorient the side chains of Trp 136 and Tyr 190 for the optimal binding and alignment of the phosphocholine moiety. Consistent with these conformational changes, LicC operates via a compulsory ordered kinetic mechanism. The structures explain the substrate specificity of LicC for CTP and phosphocholine and implicate a direct role for Mg 2؉ in aligning phosphocholine for in-line nucleophilic attack and stabilizing the negative charge that develops in the pentacoordinate transition state. These results provide a structural basis for assigning a specific role for magnesium in the catalytic mechanism of pneumococcal LicC.Choline metabolism plays a key role in cell separation, transformation, autolysis, and pathogenicity of Streptococcus pneumoniae. The only known metabolic fate of choline is to decorate the teichoic and lipoteichoic acids of the cell wall, and choline is an essential nutrient for S. pneumoniae (1). The cell surface P-Cho 1 facilitates the interaction with the host surface and induces attachment and invasion (2, 3). The importance of choline in pathogenesis is not confined to S. pneumoniae but also plays a role in Hemophilus influenzae (4 -7), Pseudomonas aeruginosa, and Neisseria gonorrhoeae (8,9). In addition, cell wall P-Cho serves as the scaffold for a group of choline-binding proteins that are secreted from the cells and subsequently attached to the cell surface by their homologous choline-binding domains (see Ref. 10 and references therein). These cholinebinding proteins are essential for many aspects of S. pneumoniae cell physiology including competence and stationary phase lysis.The pathway for choline metabolism in S. pneumoniae and H. influenzae has been hypothesized to consist of a choline transport system, a choline kinase, CTP:phosphocholine cytidylyltransferase (CCT), and a choline phosphotransferase that transfers P-Cho from CDP-Cho to either lipoteichoic acid or lipopolysaccharide (5). The existence of this pathway is supported by the detection of choline kinase and CCT activity in crude extracts of S. pneumoniae (11,12). Genetic elements required for choline incorporation into the lipopolysaccharide of H. influenzae are found in the lic1 locus, which contains four open reading frames. The hypothesis drawn from the bioinformatic analysis of the lic1 locus (4) is that licA corresponds to choline kinase based on a 31% identity to the choline kinase of Saccharomyces cerevisiae over the short span of 40 amino acids between r...

This clinical research study was designed to evaluate the efficacy of a new herbal product, EstroG-100, containing a mixture of standardized extracts of Cynanchum wilfordii, Phlomis umbrosa and Angelica gigas, on menopausal symptoms. This randomized double-blind, placebo-controlled trial was performed for 12 weeks with 64 pre-, peri- and postmenopausal White Hispanic, White non-Hispanic and African American women who were randomly allocated to either the EstroG-100 group (n = 31) or the placebo group (n =  33). Primary end-points were the mean change in scores of the Kupperman menopause index (KMI) that evaluates 11 symptoms, and the mean change in scores of vaginal dryness. The mean KMI score was significantly reduced in the EstroG-100 group from 29.5 ± 7.4 at baseline to 11.3 ± 5.8 (p < 0.01) compared with change of the placebo group (29.2 ± 6.6 at baseline vs 23.7 ± 7.7 at week 12). The constituting symptoms of vasomotor, paresthesia, insomnia, nervousness, melancholia, vertigo, fatigue and rheumatic pain were significantly improved in the EstroG-100 group in comparison with the placebo group (p < 0.05). Statistically significant improvement in vaginal dryness in the EstroG-100 group was also observed compared with that of the placebo group (p < 0.05). In conclusion, EstroG-100 significantly improved the menopausal symptoms of pre-, peri- and post-menopausal women without weight gain or any serious side effects.

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Mitochondrial aldehyde dehydrogenase (ALDH2) is mainly responsible for the oxidation of acetaldehyde generated during alcohol oxidation in vivo. Cytochrome P-4502E1 (CYP2E1), a liver microsomal enzyme, also metabolizes acetaldehyde and ethanol. Genetic polymorphism of ALDH2 and CYP2E1 was investigated among 481 Korean adults. A new restriction fragment-length polymorphism method was developed to determine the genotype of the ALDH2 alleles. This method proved to be simpler and faster than the hybridization method using allele-specific oligonucleotide probes and polymerase chain reaction-directed mutagenesis. The allele frequencies of ALDH2(1) and ALDH2(2) were 0.840 and 0.160, respectively. This allele frequency of ALDH2(2) is less than in Japanese people. Genetic polymorphism of CYP2E1 was investigated using polymerase chain reaction and restriction fragment-length polymorphism. The estimated allele frequencies for c1 and c2 were 0.808 and 0.192.

The herbs danggui (Angelica gigas) and clove (Eugenia caryophyllata) and 4 natural antioxidants were combined in order to investigate whether or not they exhibited synergistic effects (SEs) on DPPH radical scavenging capacity. SEs were determined using the ratio between experimental scavenging capacity (ESC) and theoretical scavenging capacity (TSC). In all tested mixtures, SEs were observed, indicating ESC/TSC ratios greater than 1. The highest SE (p<0.01) was observed for the solution combining α-tocopherol (20 µg/mL) and quercetin (0.7 µg/mL) with danggui of 0.3 mg/mL and clove of 0.05 mg/mL. The addition of lipid-soluble antioxidants resulted in greater SEs than the addition of water-soluble antioxidants. The excellent SE appeared when quercetin was added to the herb mixture, while the addition of ascorbic acid did not result in SE. The results indicate that the combinations of compounds with different antiradical effects may more effectively protect oxidative stress than alone.