Structural organization and phase behavior of phospholipid fractions of actinobacteria in relation to storage conditions

X-ray diffraction analysis provided information on structural organization, phase behavior, and stability of the major parameters of phospholipid fractions of the cell membranes of actinobacteria strains Streptomyces hygroscopicus RIA 1433, Nonomuraea roseoviolacea subsp. carminata INA 4281, and Nonomuraea sp. INA 34-06 depending on the storage conditions and hydration level. Phospholipids of S. hygroscopicus were shown to form densely packed multilamellar layers. The phospholipid fraction of this microorganism was notable for homogeneity and stability of its structural organization upon storage at 4°C during 10 months. On the contrary, lipids of the phospholipid fractions of N. roseoviolacea subsp. carminata INA 4281 and Nonomuraea sp. INA 34-06 formed lamellar and inverted hexagonal (HII) phases. The phase depended on hydration level and changed in the course of storage. We assume that the revealed differences in phase structural organization of actinobacterial phospholipid fractions may indicate long-term stability of their membrane structures.