Gazing into the remarkable world of non-heme catalases through the window of the cyanobacterial Mn-catalase ‘KatB’

Catalases, enzymes that decompose H2O2, are broadly categorized as heme catalases or non-heme catalases. The non-heme catalases are also known as Mn-catalases as they have Mn atoms in their active sites. However, unlike the well characterized heme-catalases, the study of Mn-catalases has gained impo...

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Published in:Free radical biology & medicine 2020-11, Vol.160, p.480-487
Main Authors: Ballal, Anand, Chakravarty, Dhiman, Bihani, Subhash C., Banerjee, Manisha
Format: Article
Language:English
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Summary:Catalases, enzymes that decompose H2O2, are broadly categorized as heme catalases or non-heme catalases. The non-heme catalases are also known as Mn-catalases as they have Mn atoms in their active sites. However, unlike the well characterized heme-catalases, the study of Mn-catalases has gained importance only in the last few years. The filamentous, heterocystous, N2-fixing cyanobacterium Anabaena PCC 7120, shows the presence of two Mn-catalases, KatA and KatB, but lacks heme catalases. Of the two Mn-catalases, KatB, which is induced by salt/desiccation, plays a major role in overcoming salinity/oxidative stress. In this mini review, we have summarized the recent advances made in the field of Mn-catalases, particularly KatB, and have interpreted these results in the larger context of stress physiology. These aspects bring to the fore the distinctive biochemical/structural properties of Mn-catalases and furthermore highlight the in vivo importance of these enzymes in adapting to oxidative stresses. [Display omitted] •Mn-catalases are structurally distinct from the well-characterized heme catalases.•Environmental stresses that exacerbate ROS induce the Mn-catalase KatB in Anabaena.•KatB efficiently detoxifies H2O2, enabling survival under salinity/oxidative stress.•N-terminal of Mn-catalases is essential for assembly of compact, robust hexamers.•Mn-catalases show distinct active sites, providing templates for catalase mimetics.
ISSN:0891-5849
1873-4596
DOI:10.1016/j.freeradbiomed.2020.08.013