Phasins, the multifacetic polyhydroxyalkanoate granule associated proteins.

PETTINARI M. JULIA; MEZZINA, MARIELA

APPLIED AND ENVIRONMENTAL MICROBIOLOGY

AMER SOC MICROBIOLOGY

Lugar: Washington; Año: 2016 vol. 82 p. 5060 - 5067

0099-2240

Phasins are the major polyhydroxyalkanoate (PHA) granule associated proteins. They promote bacterial growth and PHA synthesis and affect the number, size and distribution of the granules. These proteins can be classified in 4 families with distinctive characteristics. Low resolution structural studies and in silico predictions were performed in order to elucidate the structure of different phasins. Most of these proteins share some common structural features such as a preponderant α-helix composition, the presence of disordered regions that provide flexibility to the protein and coiled-coil interacting regions that form oligomerization domains. Due to their amphiphilic nature, these proteins play an important structural function forming an interphase between the hydrophobic content of PHA granules and the hydrophilic cytoplasm content. Phasins have been observed to affect both PHA accumulation and utilization. Apart from their role as granule structural proteins, phasins have a remarkable variety of additional functions. Different phasins have been described to i) activate PHA depolymerization, ii) increase expression and activity of PHA synthases, iii) participate in PHA granule segregation, and iv) have both in vivo and in vitro chaperone activities. These properties suggest that phasins could play an active role in PHA related stress protection and fitness enhancement. Due to their granule binding capacity and structural flexibility, several biotechnological applications have been developed using different phasins increasing the interest on the study of these remarkable proteins.