Preliminary characterization of a novel β-agarase from Thalassospira profundimonas.

Cheng Zeng,Yi Zhang,Shaoxiao Zeng,Longtao Zhang,Song Miao,Baodong Zheng

doi:10.1186/s40064-016-2748-6

Abstract

BackgroundThe objective of this study was to characterize the agarase from a newly isolated agarolytic bacterium Thalassospira profundimaris fst-13007.ResultsAgarase-fst was purified to homogeneity which apparent molecular weight was 66.2 kDa. Its activity was optimal at 45 °C and pH 8 and was stable at pH 5–9 or 30–50 °C. Agarase-fst required Mn2+ for agarase activity and inhibition by Cu2+, Fe3+ and EDTA. Tests of hydrolysis pattern and substrate specificity, TLC analysis and mass spectrometry of the hydrolysis products revealed that it is an endo-type β-agarase hydrolyzing agarose into neoagarobiose, neoagarotetraose and neoagarohexaose. Results of MALDI-TOF-TOF/MS indicate that it lack of homology to previously identified proteins and present conserved domain of β-agarase.ConclusionAgarase-fst from T. profundimaris fst-13007 was confirmed to be a novel endo-type β-agarase.

Highlights

The objective of this study was to characterize the agarase from a newly isolated agarolytic bacterium Thalassospira profundimaris fst-13007
Agarases are glycoside hydrolases (GHs) that catalyse the degrading of agarose, which is classified into β-agarase (EC 3.2.1.81), α-agarases (E.C.3.2.1.158), and β-porphyranases (EC 3.2.1.-) (Fu and Kim 2010). β-agarases hydrolyze agarose at the β-1,4 linkages into series of neoagarooligosaccharides (NAOS) with D-galactose at the reducing end
Fst-13007 was grouped into the clade composed of annotated T. profundimaris species (Fig. 3)

Summary

Introduction

The objective of this study was to characterize the agarase from a newly isolated agarolytic bacterium Thalassospira profundimaris fst-13007. Agarases are glycoside hydrolases (GHs) that catalyse the degrading of agarose, which is classified into β-agarase (EC 3.2.1.81), α-agarases (E.C.3.2.1.158), and β-porphyranases (EC 3.2.1.-) (Fu and Kim 2010). Β-agarases hydrolyze agarose at the β-1,4 linkages into series of neoagarooligosaccharides (NAOS) with D-galactose at the reducing end. Α-agarases hydrolyze agarose at the α-1, 3 linkages into agarooligosaccharides with 3,6-anhydro-l-galactose at the reducing end (Potin et al 1993). Β-Porphyranases hydrolyze porphyrobiose at the β-1,4 linkages into series of porphyrooligosaccharides with D-galactose at the reducing end (Hehemann et al 2010). A novel agarase was firstly purified from a newly isolated agarolytic bacterium, Thalassospira profundimaris

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