What keeps polyhydroxyalkanoates in bacterial cells amorphous? A derivation from stress exposure experiments

0517409 - BC 2020 RIV DE eng J - Journal Article
Sedláček, P. - Slaninova, E. - Enev, V. - Koller, M. - Nebesářová, Jana - Marová, I. - Hrubanová, Kamila - Krzyžánek, Vladislav - Samek, Ota - Obruča, S.
What keeps polyhydroxyalkanoates in bacterial cells amorphous? A derivation from stress exposure experiments.
Applied Microbiology and Biotechnology. Roč. 103, č. 4 (2019), s. 1905-1917. ISSN 0175-7598. E-ISSN 1432-0614
R&D Projects: GA MŠMT(CZ) LM2015062; GA ČR(CZ) GA19-20697S
Institutional support: RVO:60077344 ; RVO:68081731
Keywords : transform infrared-spectroscopy * secondary structure * ralstonia-eutropha * granules * proteins * 3-hydroxybutyrate * hydroxybutyrate * crystallization * synthase * behavior * Polyhydroxyalkanoates crystallization * Intracellular granules * Stress conditions
OECD category: Genetics and heredity (medical genetics to be 3); Electrical and electronic engineering (UPT-D)
Impact factor: 3.530, year: 2019
Method of publishing: Limited access
https://link.springer.com/article/10.1007%2Fs00253-018-09584-z

Polyhydroxyalkanoates (PHA) are storage polymers accumulated by numerous prokaryotes in form of intracellular granules. Native PHA granules are formed by amorphous polymer which reveals considerably higher elasticity and flexibility as compared to crystalline pure PHA polymers. The fact that bacteria store PHA in amorphous state has great biological consequences. It is not clear which mechanisms protect amorphous polymer in native granules from transition into thermodynamically favorable crystalline state. Here, we demonstrate that exposition of bacterial cells to particular stressors induces granules aggregation, which is the first but not sufficient condition for PHA crystallization. Crystallization of the polymer occurs only when the stressed bacterial cells are subsequently dried. The fact that both granules aggregation and cell drying must occur to induce crystallization of PHA indicates that both previously suggested hypotheses about mechanisms of stabilization of amorphous state of native PHA are valid and, in fact, both effects participate synergistically. It seems that the amorphous state of the polymer is stabilized kinetically by the low rate of crystallization in limited volume in small PHA granules and, moreover, water present in PHA granules seems to function as plasticizer protecting the polymer from crystallization, as confirmed experimentally for the first time by the present work.
Permanent Link: http://hdl.handle.net/11104/0302725