• Journal of Microbiology and Biotechnology
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• v.8 no.4
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• pp.378-387
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• 1998

The DNA sequence immediately following the xynA gene of Bacillus stearothermophilus 236 ［about l-kb region downstream from the translational termination codon (TAA) of the xynA gene］was found to have an ability to enhance the xylanase activity of the upstream xynA gene. An 849-bp ORF was identified in the downstream region, and the ORF was confirmed to encode a novel protein of 283 amino acids designated as XaiF (xylanase-activity-increasing factor). From the nucleotide sequence of the xaiF gene, the molecular mass and pI of XaiF were deduced to be 32,006 Da and 4.46, respectively. XaiF was overproduced in the E. coli cells from the cloned xaiF gene by using the T7 expression system. The transcriptional initiation site was determined by primer extension analysis and the putative promoter and ribosome binding regions were also identified. Blast search showed that the xaiF and its protein product had no homology with any gene nor any protein reported so far. Also, in B. subtilis, the xaiF trans-activated the xylanase activity at the same rate as in E. coli. In contrast, xaiF had no activating effect on the co-expressed ${\beta}-xylosidase$ of the xylA gene derived from the same strain of B. stearothermophilus. In addition, the intracellular and extracellular fractions from the E. coli cells carrying the plasmid-borne xaiF gene did not increase the isolated xylanase activity, indicating that the protein-protein interaction between XynA and XaiF was not a causative event for the xylanase activating effect of the xaiF gene.

• Proceedings of the Korean Journal of Food and Nutrition Conference
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• 2000.05a
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• pp.1-3
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• 2000

A kind of traditional herbal prescription, Sip-Jeon-Dae-Bo-Tang (TJ-48), has been reported to improve the general condition of cancer patients receiving chemotherapy and /or radiation therapy, and to accelerate hematopoietic recovery from bone marrow injury by mitomycin C. In the present studies, we found that hot-water extract from Atractylodes lancea DC. rhizomes contributed mainly to intestinal immune modulating activity of TJ-48 on Peyer's patch cells mediated-hematopoietic response. After the fractionation, ALR-5 II a-1-1, 5 II b-2-2 and 5 II c-3-1 were further purified from crude polysaccharide fraction. Chemical analyses of each fraction indicated that ALR-5 II a-1-1 mainly contained arabinogalactan fraction whereas ALR-5 II b-2-2 and 5 II c-3-1 mostly comprised pectic polysaccharide fractions as the active polysaccharide ingredients. In order to analyze the essential structure of the activity, ALR-5 II a-1-1 was treated by sequential enzymatic digestion using exo-${\alpha}$-L-arabinofuranosidase and exo-${\beta}$-D-(1\longrightarrow3)-galactanase. Based upon the results of chemical and MALDI-TOF-MS analyses and activity on the digested fractions, the galactosyl side chains consisting of 6-linked Galf and Galp over tetrasaccharide in ALR-5 II a-1-1 might be responsible for the potent intestinal immune modulating activity. To characterize moiety of ALR-5 II c-3-1 for the expression of activity, endo-${\alpha}$-D-(1\longrightarrow4)-polygal acturonase (GL-PGase) purified from dried leaves of Panax ginseng digested ALR-5 II c-3-1. The results of structural analyses and activity on the digested fractions showed that PG-2, which structurally resembles to rhamnogalacturonan II (RG II), and PG-3 (galacturono-oligosaccharides) contained potent intestinal immune modulating activity. Further purification of the other acidic fraction (ALR-5 II b-2-2) indicated that ALR-5 II b-2-2Bb showed that the most potent activity. ALR-5 II b-2-2Bb also contained the unusual component sugars characteristics in RG- II as well as PG-2 derived from ALR-5 II c-3-1, but it could not be digested with GL-PGase. The present studies of relationship between structures and intestinal immune modulating activity of the active polysaccharides purified from A. lancea DC. rhizomes suggested that neutral galactosyl chains consisting mainly of (1\longrightarrow6)-linked Galf and Galp, and RG- II -like moiety with unique component sugars, such as 2-Me-Xyl, 2-Me-Fuc, Api, AceA, Kdo and Dha should play an important role in the potent intestinal immune modulating action of A. lancea DC. rhizomes.