Skip to main content
Log in

Characterization of an α-agarase from Thalassomonas sp. LD5 and its hydrolysate

  • Biotechnologically relevant enzymes and proteins
  • Published:
Applied Microbiology and Biotechnology Aims and scope Submit manuscript

Abstract

It has been a long time since the first α-agarase was discovered. However, only two α-agarases have been cloned and partially characterized so far and the study of α-agarases has lagged far behind that of β-agarases. Here, we report an α-agarase, AgaD, cloned from marine bacterium Thalassomonas sp. LD5. Its cDNA consists of 4401 bp, encoding a protein of 1466 amino acids. Based on amino acid similarity, AgaD is classified into glycoside hydrolase (GH) family GH96. The recombinant enzyme gave a molecular weight of about 180 kDa on SDS-PAGE and 360 kDa on Native-PAGE indicating it acted as a dimer. However, the recombinant enzyme is labile and easy to be fractured into series of small active fragments, of which the smallest one is about 70 kDa, matching the size of catalytic module. The enzyme has maximal activity at 35 °C and pH 7.4, and shows a strong dependence on the presence of calcium ions. AgaD degrades agarose to yield agarotetraose as the predominate end product. However, the hydrolysates are rapidly degraded to odd-numbered oligosaccharides under strong alkaline condition. The spectra of ESI-MS and 1H-NMR proved that the main hydrolysate agarotetraose is degraded into neoagarotriose, bearing the sequence of G-A-G (G, d-galactose; A, 3,6-anhydro-α-l-galactose). Unlike the alkaline condition, the hydrolysates are further hydrolyzed into smaller degree polymerization (DP) of agaro-oligosaccharides (AOS) in dilute strong acid. Therefore, this study provides more insights into the properties for both the α-agarases and the AOS.

This is a preview of subscription content, log in via an institution to check access.

Access this article

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Fig. 1
Fig. 2
Fig. 3
Fig. 4
Fig. 5
Fig. 6
Fig. 7

Similar content being viewed by others

References

Download references

Funding

This study was funded by the National Natural Science Foundation of China (41376144), NSFC-Shandong Joint Fund for Marine Science Research Centers (U1606403), Science and Technology Development Plan Project of Shandong Province (2014GGH215002), and the National High-tech R&D Program of China (2014AA093504).

Author information

Authors and Affiliations

Authors

Corresponding authors

Correspondence to Xinzhi Lu or Wengong Yu.

Ethics declarations

Conflict of interest

The authors declare that they have no competing interests.

Ethics approval

This article does not contain any studies with human participants or animals performed by any of the authors.

Electronic supplementary material

ESM 1

(PDF 402 kb)

Rights and permissions

Reprints and permissions

About this article

Check for updates. Verify currency and authenticity via CrossMark

Cite this article

Zhang, W., Xu, J., Liu, D. et al. Characterization of an α-agarase from Thalassomonas sp. LD5 and its hydrolysate. Appl Microbiol Biotechnol 102, 2203–2212 (2018). https://doi.org/10.1007/s00253-018-8762-6

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1007/s00253-018-8762-6

Keywords

Navigation