• Mass Spectrometry Letters
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• v.6 no.3
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• pp.80-84
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• 2015

Here, we demonstrate the use of MALDI-TOF as a fast and simple analytical approach to evaluate the DNA-binding capability of various peptides. Specifically, by varying the amino acid sequence of the peptides consisting of lysine (K) and tryptophan (W), we identified peptides with strong DNA-binding capabilities using MALDI-TOF. Mass spectrometric analysis reveals an interesting novel finding that lysine residues show sequence selective preference, which used to be considered as mediator of electrostatic interactions with DNA phosphate backbones. Moreover, tryptophan residues show higher affinity to DNA than lysine residues. Since there are numerous possible combinations to make peptide oligomers, it is valuable to introduce a simple and reliable analytical approach in order to quickly identify DNA-binding peptides.

• Journal of Microbiology and Biotechnology
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• v.11 no.5
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• pp.798-803
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• 2001

Peptide synthetases produced from various microorganisms are multifunctional enzyme complexes and their substrates are recognized and activated by adenylation domains. To identify the substrate specificity of the peptide synthetase isolated from Bacillus subtilis 713, known to produce an antifungal peptide, two adenylation domains containing the minimal functional portion were expressed and purified. ATP-ppi exchange experiments and kinetic studies revealed that the two adenylation enzymes had a substrate specificity to $_{L}-lysine{\;}and{\;}_{L}-tryptophan$, respectively. In addition, based on a signature sequence comparison, the substrate of the third domain was predicted to be L-glutamic acid. These results suggest that this peptide synthetase is novel because there has been no previous report on a peptide synthetase that uses $_{L}-lysine,{\;}_{L}-tryptophan,{\;}and{\;}_{L}-glutamic$ acid as substrates in that order.

• Applied Biological Chemistry
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• v.22 no.1
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• pp.1-9
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• 1979

The physical and chemical properties of ${\gamma}-conglycinin$ of soybean (Glycine max) were investigated. The soybean protein extracted from soybean meal using 0.2M NaCl solution at pH 4.5 was passed through a Sephadex G-150 column to isolate 7S globulin. ${\gamma}$-Conglycinin was isolated and purified from the 7S globulin with a DEAE Sephadex A-50 column chromatography. The protein preparation was pure on immunoelectrophoresis, polyacrylamide gel electrophoresis and gel isoelectric fouling. It had an isoelectric point at pH 5.4 and contained 16.12% nitrogen, 4.18% mannose and 1.21% glucosamine. Amino acid composition, in general, shaved that ${\gamma}-conglycinin$ contained higher contents of lysine, dicarboxylic acids and ammonia nitrogen, and lower contents of sulfur-containing amino acids and tryptophan. The subunits of ${\gamma}-conglycinin$ were distributed in the range of pH 4.6-5.5. The subunits located in the pH region of 4.6-5.0 and 5.0-5.5 were glycopeptides (molecular weight of 38,000) and simple peptide (MW of 32,000), respectively.