Phasins, Multifaceted Polyhydroxyalkanoate Granule-Associated Proteins

Mezzina, Mariela P.; Pettinari, M. Julia

doi:10.1128/aem.01161-16

Cited by 107 publications

(62 citation statements)

References 58 publications

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“…Polyhydroxyalkanoic acid regulation and accumulation is important for growth of R. sphaeroides Phasins (PhaP) are specialized proteins that bind to polyhydroxyalkanoic acid (PHA) granules and assist granule formation. Phasins may also have chaperone activities that enhance survival during stress (Mezzina and Pettinari, 2016). PHA granules are a primary form of carbon storage, and PHA granules and accompanying phasins are known to be produced by R. sphaeroides (Wieczorek et al, 1996).…”

Section: Impact Of Selected Genes On Growthmentioning

confidence: 99%

Adaptation of the Alphaproteobacterium Rhodobacter sphaeroides to stationary phase

McIntosh

Eisenhardt

Remes

et al. 2019

Environmental Microbiology

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Summary Exhaustion of nutritional resources stimulates bacterial populations to adapt their growth behaviour. General mechanisms are known to facilitate this adaptation by sensing the environmental change and coordinating gene expression. However, the existence of such mechanisms among the Alphaproteobacteria remains unclear. This study focusses on global changes in transcript levels during growth under carbon‐limiting conditions in a model Alphaproteobacterium, Rhodobacter sphaeroides, a metabolically diverse organism capable of multiple modes of growth including aerobic and anaerobic respiration, anaerobic anoxygenic photosynthesis and fermentation. We identified genes that showed changed transcript levels independently of oxygen levels during the adaptation to stationary phase. We selected a subset of these genes and subjected them to mutational analysis, including genes predicted to be involved in manganese uptake, polyhydroxybutyrate production and quorum sensing and an alternative sigma factor. Although these genes have not been previously associated with the adaptation to stationary phase, we found that all were important to varying degrees. We conclude that while R. sphaeroides appears to lack a rpoS‐like master regulator of stationary phase adaptation, this adaptation is nonetheless enabled through the impact of multiple genes, each responding to environmental conditions and contributing to the adaptation to stationary phase.

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Section: Impact Of Selected Genes On Growthmentioning

confidence: 99%

Adaptation of the Alphaproteobacterium Rhodobacter sphaeroides to stationary phase

McIntosh

Eisenhardt

Remes

et al. 2019

Environmental Microbiology

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“…Microbial PHA preparations usually contain adsorbed phospholipids as well (19), although the actual occurrence of this coating in vivo has been recently questioned and might represent a purification artifact from the cell extracts (20)(21)(22). Phasins, the main component of GAPs, have a relevant role in the PHA intracellular metabolism, participating in events that include the control of the size, number, and localization of granules in the cell (23,24). The high affinity of phasins for PHA suggests the application of such polypeptides as affinity tags for the immobilization of proteins on polyester granules.…”

Section: Importancementioning

confidence: 99%

Poly-3-Hydroxybutyrate Functionalization with BioF-Tagged Recombinant Proteins

Bello-Gil

Maestro

Fonseca

et al. 2018

Appl Environ Microbiol

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Polyhydroxyalkanoates (PHAs) are biodegradable polyesters that accumulate in the cytoplasm of certain bacteria. One promising biotechnological application utilizes these biopolymers as supports for protein immobilization. Here, the PHA-binding domain of the KT2440 PhaF phasin (BioF polypeptide) was investigated as an affinity tag for the functionalization of poly-3-hydroxybutyrate (PHB) particles with recombinant proteins, namely, full-length PhaF and two fusion proteins tagged to BioF (BioF-C-LytA and BioF-β-galactosidase, containing the choline-binding module C-LytA and the β-galactosidase enzyme, respectively). The protein-biopolyester interaction was strong and stable at a wide range of pHs and temperatures, and the bound protein was highly protected from self-degradation, while the binding strength could be modulated by coating with amphiphilic compounds. Finally, BioF-β-galactosidase displayed very stable enzymatic activity after several continuous activity-plus-washing cycles when immobilized in a minibioreactor. Our results demonstrate the potentialities of PHA and the BioF tag for the construction of novel bioactive materials. Our results confirm the biotechnological potential of the BioF affinity tag as a versatile tool for functionalizing PHA supports with recombinant proteins, leading to novel bioactive materials. The wide substrate range of the BioF tag presumably enables protein immobilization of virtually all natural PHAs as well as blends, copolymers, or artificial chemically modified derivatives with novel physicochemical properties. Moreover, the strength of protein adsorption may be easily modulated by varying the coating of the support, providing new perspectives for the engineering of bioactive materials that require a tight control of protein loading.

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“…In the recent years, a large number of phasins have been identified, constituting a phylogenetically heterogeneous group of proteins. We will review the current knowledge on the most representative phasins participating in important biological functions (summarized in Table ) such as the formation of network‐like covers on the PHA granule surface (Dennis et al ., , ; Pfeiffer and Jendrossek, ) or the regulation of the synthesis, morphology, distribution during cell division and degradation of the storage granules (Mezzina and Pettinari, ). Finally, the biotechnological potential of this group of proteins will be discussed.…”

Section: Introductionmentioning

confidence: 99%

Polyhydroxyalkanoate‐associated phasins as phylogenetically heterogeneous, multipurpose proteins

Maestro

Sanz

2017

Microbial Biotechnology

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SummaryPolyhydroxyalkanoates (PHAs) are natural polyesters of increasing biotechnological importance that are synthesized by many prokaryotic organisms as carbon and energy storage compounds in limiting growth conditions. PHAs accumulate intracellularly in form of inclusion bodies that are covered with a proteinaceous surface layer (granule‐associated proteins or GAPs) conforming a network‐like surface of structural, metabolic and regulatory polypeptides, and configuring the PHA granules as complex and well‐organized subcellular structures that have been designated as ‘carbonosomes’. GAPs include several enzymes related to PHA metabolism (synthases, depolymerases and hydroxylases) together with the so‐called phasins, an heterogeneous group of small‐size proteins that cover most of the PHA granule and that are devoid of catalytic functions but nevertheless play an essential role in granule structure and PHA metabolism. Structurally, phasins are amphiphilic proteins that shield the hydrophobic polymer from the cytoplasm. Here, we summarize the characteristics of the different phasins identified so far from PHA producer organisms and highlight the diverse opportunities that they offer in the Biotechnology field.

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Phasins, Multifaceted Polyhydroxyalkanoate Granule-Associated Proteins

Cited by 107 publications

References 58 publications

Adaptation of the Alphaproteobacterium Rhodobacter sphaeroides to stationary phase

Adaptation of the Alphaproteobacterium Rhodobacter sphaeroides to stationary phase

Poly-3-Hydroxybutyrate Functionalization with BioF-Tagged Recombinant Proteins

Polyhydroxyalkanoate‐associated phasins as phylogenetically heterogeneous, multipurpose proteins

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