Search results for "GroEL"
showing 10 items of 24 documents
Multilocus typing for characterization of ‘Candidatus Phytoplasma asteris’-related strains in several ornamental species in Italy
2018
Different ornamental plants showing symptoms referable to phytoplasma presence and collected between 1993 and 2015 in various floricultural areas in north and south of Italy, enclosing Sicily, resulted to be infected by ‘Candidatus Phytoplasma asteris’-related strains, and after PCR/RFLP identification on 16Sr gene were assigned to 16SrI-B subgroup. These infected samples were employed for phytoplasma strain differentiation on tuf, groel, rp and amp genes. In particular, the 23 phytoplasma strains employed were from hydrangea (5), primula (3), gentian (2), petunia (2) and gerbera (1) samples showing flower virescence; from gladiolus samples both in vivo and in micropropagation (2) showing t…
Structure and Stability of Hsp60 and Groel in Solution
2016
Molecular chaperones are a class of proteins able to prevent non-specific aggregation of mitochondrial proteins and to promote their proper folding. Among them, human Hsp60 is currently considered as a ubiquitous molecule with multiple roles both in maintaining health conditions and as a trigger of several diseases. Of particular interest is its role in neurodegenerative disorders since it is able to inhibit the formation of amyloid fibrils.Hsp60 structure was considered, until recent years, analogue to the one of its bacterial homolog GroEL, one of the most investigated chaperones, whose crystallographic structure is a homo-tetradecamer, made up of two seven member rings. On the contrary, …
Chaperonin of Group I: Oligomeric spectrum and biochemical and biological implications
2018
Chaperonins play various physiological roles and can also be pathogenic. Elucidation of their structure, e.g., oligomeric status and post-translational modifications (PTM), is necessary to understand their functions and mechanisms of action in health and disease. Group I chaperonins form tetradecamers with two stacked heptameric rings. The tetradecamer is considered the typical functional complex for folding of client polypeptides. However, other forms such as the monomer and oligomers with smaller number of subunits than the classical tetradecamer, also occur in cells. The properties and functions of the monomer and oligomers, and their roles in chaperonin-associated diseases are still inc…
Complex Destabilization in the Mitochondrial Chaperonin Hsp60 Leads to Disease.
2020
Several neurological disorders have been linked to mutations in chaperonin genes and more specifically to the HSPD1 gene. In humans, HSPD1 encodes for the mitochondrial Heat Shock Protein 60 (mtHsp60) chaperonin, which carries out essential protein refolding reactions that help maintain mitochondrial and cellular homeostasis. It functions as a macromolecular complex that provides client proteins an environment that favors proper folding in an ATP dependent manner. It has been established that mtHsp60 plays a crucial role in the proper folding of mitochondrial proteins involved in ATP producing pathways. Recently, various single-point mutations in the mtHsp60 encoding gene have been directly…
The biofilm mode of life boosts the anti-inflammatory properties ofLactobacillus
2014
Summary The predominant form of life for microorganisms in their natural habitats is the biofilm mode of growth. The adherence and colonization of probiotic bacteria are considered as essential factors for their immunoregulatory function in the host. Here, we show that Lactobacillus casei ATCC334 adheres to and colonizes the gut of zebrafish larvae. The abundance of pro-inflammatory cytokines and the recruitment of macrophages were low when inflammation was induced in probiotic-fed animals, suggesting that these bacteria have anti-inflammatory properties. We treated human macrophage-differentiated monocytic THP-1 cells with supernatants of L. casei ATCC334 grown in either biofilm or plankto…
Nested MWC model describes hydrolysis of GroEL without assuming negative cooperativity in binding
2002
Folding assistance and ATPase activity of GroEL are based on the existence of different conformations. In order to characterise these conformations, published data on steady state ATPase activity in the absence of GroES were reanalysed simultaneously in terms of the Nested MWC model. This model is a hierarchical extension of the symmetry-model of Monod et al. [J. Mol. Biol. 12 (1965) 88]. An unique set of GroEL specific parameters was obtained. This set was supported by comparison of predictions arising from this set of values with experimental data for hydrolysis of ATP in the presence of ADP and ATPgammaS, binding of ATPgammaS and ADP to GroEL in the absence of ATP, and binding of ATP as …
Nested allosteric interactions in extracellular hemoglobin of the leech Macrobdella decora
2003
Hemoglobin from the leech Macrobdella decora belongs to the class of giant extracellular hexagonal bilayer globin structures found in annelid and vestimentiferan worms. These complexes consist of 144 heme-bearing subunits, exhibit a characteristic quaternary structure (2 × (6 × (3 × 4))), and contain tetramers as basic substructures that express cooperative oxygen binding and thus provide a structural basis for a hierarchy in allosteric interactions. A thorough analysis of the isolated tetramer indicates that it functions as a trimer of cooperatively interacting subunits and a non-cooperative monomer rather than as four interacting subunits. A thermodynamic analysis of the whole molecule fa…
Hsp60 Inhibitors and Modulators
2019
In this chapter, we focus on the 60 KDa Heat Shock Protein (Hsp60) and discuss some of its biological, molecular and pathological features. The structural and mechanistic aspect of the Hsp60 folding cycle will be also presented. We further illustrate how Hsp60 may be involved in many diseases and therefore considered as an effective therapeutic or theranostic target. Finally, the state-of-the-art on the development of Hsp60 and bacterial GroEL inhibitors and modulators of their expression will be illustrated. This is discussed in the light of a negative chaperonotherapy, and the consequent development of inhibitors, as well as positive chaperonotherapy, in the event its excessive activity i…
(DIS)Assembly and Structural Stability of mtHsp60 and its Precursor NaÏve Form
2015
Heat shock protein 60kDa is a molecular chaperone (GroEL human homolog) that assists protein folding in mitochondria (mtHsp60). It is synthesized in the cell cytoplasm as a higher molecular weight precursor form (p-mtHsp60) containing a N-terminal targeting sequence, that is cleaved after import into the mitochondrial matrix [1, 2].It has been established, and demonstrated by various techniques, Hsp60 can accumulate in the cytosol, in various pathological conditions (i.e., cancer and chronic inflammatory diseases). The cytosolical Hsp60 accumulation mechanism may occur with or without mitochondrial release concomitantly, so that in the cytosol the two types of 60 kDa chaperonin proteins, (m…
GroEL and the maintenance of bacterial endosymbiosis
2004
Many eukaryotic organisms have symbiotic associations with obligate intracellular bacteria. The clonal transmission of endosymbionts between host generations should lead to the irreversible fixation of slightly deleterious mutations in their non-recombinant genome by genetic drift. However, the stability of endosymbiosis indicates that some mechanism is involved in the amelioration of the effects of these mutations. We propose that the chaperone GroEL was involved in the acquisition of an endosymbiotic lifestyle not only by means of its over-production, as proposed by Moran, but also by its adaptive evolution mediated by positive selection to improve the interaction with the unstable endosy…