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J Gen Appl Microbiol. 2019 Jan 24;64(6):276-283. doi: 10.2323/jgam.2018.02.002. Epub 2018 May 30.

Characterization and overexpression of a glycosyl hydrolase family 16 β-agarase Aga0917 from Pseudoalteromonas fuliginea YTW1-15-1.

Author information

1
Synthetic Biology Engineering Lab of Henan Province, School of Life Sciences and Technology, Xinxiang Medical University.

Abstract

A gene (aga0917) encoding a putative β-agarase was identified from the genome of Pseudoalteromonas fuliginea YTW1-15-1. The nucleotide sequence analysis revealed that aga0917 had significant homology to the agarase genes of the GH16 family. aga0917 encodes a putative protein of 290 amino acids with an estimated molecular mass of 32.5 kDa, including a 21-amino acid signal peptide. A gene fragment encoding only the putative mature form of Aga0917 (269 amino acids) was overexpressed in Escherichia coli BL21 (DE3) pLysS as a 6 × histine-tagged fusion protein (rmAga0917). The Km, Vmax, and kcat for agarose of rmAga0917 were 39.6 mg/mL, 334 (U/mg) of protein, and 178 (1/s), respectively. According to the results of thin-layer chromatography and mass spectrometry analysis, the main end product from agarose with rmAga0917 was neoagarotetraose, in addition to a small amount of neoagarobiose. Notably, the recombinant protein rmAga0917 showed optimum activity at 60°C and retained approximately 100% agarolytic activity after being kept at 40°C for 1 h and 57% residual activity after incubation at 50°C for 1 h. The rmAga0917 exhibited maximum agarase activity at pH 6.0, and retained more than 80% of activity after incubation over a range of pH 4.0-9.0 for 1 h at 4°C.

KEYWORDS:

Aga0917; Pseudoalteromonas fuliginea; characterizations; neoagarotetraose; thermostability; β-agarase

PMID:
29848882
DOI:
10.2323/jgam.2018.02.002
[Indexed for MEDLINE]
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