title: Structural and functional diversity in the family of small heat shock proteins from the parasite Toxoplasma gondii.
abstract: Small heat shock proteins (sHsps) are ubiquitous molecular chaperones which prevent the nonspecific aggregation of non-native proteins. Five potential sHsps exist in the parasite Toxoplasma gondii. They are located in different intracellular compartments including mitochondria and are differentially expressed during the parasite's life cycle. Here, we analyzed the structural and functional properties of all five proteins. Interestingly, this first in vitro characterization of sHsps from protists showed that all T. gondii sHsps exhibit the characteristic properties of sHsps such as oligomeric structure and chaperone activity. However, differences in their quaternary structure and in their specific chaperone properties exist. On the structural level, the T. gondii sHsps can be divided in small (12-18 subunits) and large (24-32 subunits) oligomers. Furthermore, they differ in their interaction with non-native proteins. While some bind substrates tightly, others interact more transiently. The chaperone activity of the three more mono-disperse T. gondii sHsps is regulated by temperature with a decrease in temperature leading to the activation of chaperone activity, suggesting an adaption to specific steps of the parasite's life cycle.
authors.affiliation: Laboratorio de Parasitologia Molecular, Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús, Chascomús, Argentina.
authors.forename: Natalia
authors.initials: N
authors.lastname: de Miguel
authors.forename: Nathalie
authors.initials: N
authors.lastname: Braun
authors.forename: Alexander
authors.initials: A
authors.lastname: Bepperling
authors.forename: Thomas
authors.initials: T
authors.lastname: Kriehuber
authors.forename: Andreas
authors.initials: A
authors.lastname: Kastenmüller
authors.forename: Johannes
authors.initials: J
authors.lastname: Buchner
authors.forename: Sergio O
authors.initials: SO
authors.lastname: Angel
authors.forename: Martin
authors.initials: M
authors.lastname: Haslbeck
mesh_terms: D020816:Amino Acid Motifs / Q000502:physiology; D000818:Animals; D050888:Heat-Shock Proteins, Small / Q000235:genetics* / Q000378:metabolism; D010802:Phylogeny; D020836:Protein Structure, Quaternary / Q000502:physiology; D015800:Protozoan Proteins / Q000235:genetics* / Q000378:metabolism; D013329:Structure-Activity Relationship; D014122:Toxoplasma / Q000235:genetics* / Q000378:metabolism
chemical_list: D050888:Heat-Shock Proteins, Small; D015800:Protozoan Proteins