The globins of cold-adapted Pseudoalteromonas haloplanktis TAC125

From the structure to the physiological functions

Daniela Giordano, Daniela Coppola, Roberta Russo, Mariana Tinajero-Trejo, Guido di Prisco, Federico Lauro, Paolo Ascenzi, Cinzia Verde*

*Corresponding author for this work

Research output: Contribution to journalArticle

13 Citations (Scopus)

Abstract

Evolution allowed Antarctic microorganisms to grow successfully under extreme conditions (low temperature and high O2 content), through a variety of structural and physiological adjustments in their genomes and development of programmed responses to strong oxidative and nitrosative stress. The availability of genomic sequences from an increasing number of cold-adapted species is providing insights to understand the molecular mechanisms underlying crucial physiological processes in polar organisms. The genome of Pseudoalteromonas haloplanktis TAC125 contains multiple genes encoding three distinct truncated globins exhibiting the 2/2 α-helical fold. One of these globins has been extensively characterised by spectroscopic analysis, kinetic measurements and computer simulation. The results indicate unique adaptive structural properties that enhance the overall flexibility of the protein, so that the structure appears to be resistant to pressure-induced stress. Recent results on a genomic mutant strain highlight the involvement of the cold-adapted globin in the protection against the stress induced by high O2 concentration. Moreover, the protein was shown to catalyse peroxynitrite isomerisation in vitro. In this review, we first summarise how cold temperatures affect the physiology of microorganisms and focus on the molecular mechanisms of cold adaptation revealed by recent biochemical and genetic studies. Next, since only in a very few cases the physiological role of truncated globins has been demonstrated, we also discuss the structural and functional features of the cold-adapted globin in an attempt to put into perspective what has been learnt about these proteins and their potential role in the biology of cold-adapted microorganisms.

Original languageEnglish
Pages (from-to)329-389
Number of pages61
JournalAdvances in Microbial Physiology
Volume63
DOIs
Publication statusPublished - 2013
Externally publishedYes

Keywords

  • Antarctic marine bacterium
  • Cold-adapted bacterial globin
  • Pseudoalteromonas haloplanktis TAC125
  • Truncated haemoglobins

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