Identification and characterization of a hyperthermophilic GH9 cellulase from the Arctic Mid-Ocean Ridge vent field.

A novel GH9 cellulase (AMOR_GH9A) was discovered by sequence-based mining of a unique metagenomic dataset collected at the Jan Mayen hydrothermal vent field. AMOR_GH9A comprises a signal peptide, a catalytic domain and a CBM3 cellulose-binding module. AMOR_GH9A is an exceptionally stable enzyme with...

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Bibliographic Details
Published in:PLOS ONE
Main Authors: Anton A Stepnov, Lasse Fredriksen, Ida H Steen, Runar Stokke, Vincent G H Eijsink
Format: Article in Journal/Newspaper
Language:English
Published: Public Library of Science (PLoS) 2019
Subjects:
R
Q
Online Access:https://doi.org/10.1371/journal.pone.0222216
https://doaj.org/article/8c07677ca1f6436582009622431a3f7b
Description
Summary:A novel GH9 cellulase (AMOR_GH9A) was discovered by sequence-based mining of a unique metagenomic dataset collected at the Jan Mayen hydrothermal vent field. AMOR_GH9A comprises a signal peptide, a catalytic domain and a CBM3 cellulose-binding module. AMOR_GH9A is an exceptionally stable enzyme with a temperature optimum around 100°C and an apparent melting temperature of 105°C. The novel cellulase retains 64% of its activity after 4 hours of incubation at 95°C. The closest characterized homolog of AMOR_GH9A is TfCel9A, a processive endocellulase from the model thermophilic bacterium Thermobifida fusca (64.2% sequence identity). Direct comparison of AMOR_GH9A and TfCel9A revealed that AMOR_GH9A possesses higher activity on soluble and amorphous substrates (phosphoric acid swollen cellulose, konjac glucomannan) and has an ability to hydrolyse xylan that is lacking in TfCel9A.