
	Where results make sense

Topic: Chaperonins

Related Topics

Chaperonins

Plasmalemma

Chelation

Protoplast

Apoplast

	txt001jrl: Chaperonins are cell-signalling proteins: the unfolding biology of molecular chaperones
		When ATP is bound to chaperonin 60, the chaperonin 10 forms a lid on top of the chaperonin 60 barrel (Refs 19, 20), and causes the central cavity to enlarge, thus aiding protein folding.
		Chaperonin 60 preparations, even after purification by high-performance liquid chromatography (HPLC), can contain substantial amounts of other contaminating proteins (Ref. 51); thus, the reported bioactivity of the chaperonin 60 proteins could actually be due to such contaminating proteins.
		Chaperonins are released from cells and/or are expressed on external cell membranes (of both eukaryotic and prokaryotic cells), and thereby become part of the population of proteins that act as cell-to-cell signals.
	www-ermm.cbcu.cam.ac.uk /00002015h.htm (7205 words)

	biochem218 final project (Site not responding. Last check: 2007-10-21)
		Chaperonins are multisubunits assemblies that promote protein folding in concert with ATP hydrolysis and currently there are two known groups of chaperonins (Ellis and Hartl, 1996).
		The latter is a homolog of the eukaryotic chaperonin CCT/TRiC.
		Group II chaperonins in archae and in eukaryotic cytosol have been shown to use the same mechanism as group I chaperonins, comprising the binding of substrate to a central cavity (Marco 1994) and ATP dependent substrate release (Frydman 1992).
	www.stanford.edu /~lucys (2726 words)

	X-ray unit at the Center for Structural Biochemistry (Site not responding. Last check: 2007-10-21)
		Chaperonins are a family within the class of proteins known as molecular chaperones.
		Especially, chaperonins from thermophilic Archaea, are often expressed to extreme levels upon heatshock.
		Amino acid comparisons show that archaeal chaperonins are more related to the chaperonins in the eukaryotic cytosol than their counterpart in Bacteria, which are much more studied.
	www.csb.ki.se /users/xray/chaperonins.html (285 words)

	ILL : ANNUAL REPORT 2000
		Chaperonins are double-ring structures with a central cavity that provides a compartment for ATP-driven folding of proteins.
		Binding and hydrolysis of ATP are thought to switch the chaperonins between an acceptor state, in which the cavity is open to receive an unfolded or a misfolded protein (‘substrate’), and a folding-active state, encapsulating the substrate.
		The release of phosphate triggers the re-opening of the chaperonin.
	www.ill.fr /AR-00/p-52.htm (1162 words)

	Ordered Nanostructures Made Using Chaperonin Polypeptides
		Each natural chaperonin molecule comprises 14, 16, or 18 protein subunits, arranged as two stacked rings approximately 16 to 18 nm tall by approximately 15 to 17 nm wide, the exact dimensions depending on the biological species in which it originates.
		The natural role of chaperonins is unknown, but they are believed to aid in the correct folding of other proteins, by enclosing unfolded proteins and preventing nonspecific aggregation during assembly.
		Through genetic engineering of the organisms used to manufacture the chaperonins, specific sites on the chaperonin molecules and, thus, on the two-dimensional crystals can be chemically modified to react in a specific manner so as to favor the deposition of the material of the desired nanoparticles or quantum dots.
	www.nasatech.com /Briefs/May04/ARC14744.html (512 words)

	Isolation and Characterization of a Second Subunit of Molecular Chaperonin from Pyrococcus kodakaraensis KOD1: Analysis ...
		Chaperonins have been classified into two distinct groups, I and II (12).
		The molecular chaperonin TF55 from the thermophilic archaeon Sulfolobus solfataricus.
		subunit of a chaperonin from the hyperthermophilic archaeon Pyrococcus sp.
	aem.asm.org /cgi/content/full/65/4/1801 (2655 words)

	Molecular chaperonins.
		The chaperonins are all abundant constitutive proteins that increase in amount after different kinds of stress such as heat shock, bacterial infection, and an increased intracellular content of unfolded proteins.
		The larger type is called chaperonin 60 (cpn60), while the smaller type is called chaperonin 10 (cpn10).
		Bacterial and mitochondrial chaperonin 10 bind to chaperonin 60 in the presence of MgATP and then suppresses the ATPase activity of the latter.
	www.img.cas.cz /bl/62_3_193-218.htm (191 words)

	Palaeos Bacteria: Pieces: GroEL
		Chaperonins were originally characterized as a subpopulation of "heat-shock proteins," proteins whose synthesis was promoted by heat stress.
		The chaperonin was thus like a stage magician who runs a scarf through a magic ring, from which it emerges a different color.
		This generality of chaperonins became even more inexplicable when it was found that many proteins which are not chaperonin-dependent fold themselves just fine, and at about the same speed, if they are simply left to themselves in a test tube.
	www.palaeos.com /Bacteria/Pieces/GroEL.html (1472 words)

	E0049: Allosteric Mechanism of Chaperonins Studied by Single Particle Cryo EM (Site not responding. Last check: 2007-10-21)
		Chaperonins are molecular machines that recognise misfolded or unfolded proteins and enable the correct folding of an essential subset of cellular proteins.
		Access to the chamber is regulated by the nucleotide cycle, which controls the binding and release of GroES in an alternating action between the two back-to-back rings.
		Combining the cryo EM maps with the atomic structures of the domains provides a detailed structural basis for understanding the allosteric mechanism of chaperonins and control of their interactions with folding protein substrates.
	www.hwi.buffalo.edu /ACA/ACA02/abstracts/text/E0049.html (307 words)

	Chaperonins in disease: mechanisms, models, and treatments -- Ranford and Henderson 55 (4): 209 -- Molecular Pathology
		Chaperonins are oligomeric proteins that assist in the folding
		Chaperonin 60 proteins are also involved in prion diseases.
		Identification of in vivo substrates of the chaperonin GroEL.
	mp.bmjjournals.com /cgi/content/full/55/4/209 (3638 words)

	GroEL and GroES
		The three major classes of molecular chaperones are the Hsp70 (heat shock protein 70) proteins, nucleoplasmins, and the chaperonins.
		Chaperonins are large, multisubunit, cage-like proteins that are universal components of bacteria, mitochondria, and chloroplasts (Voet, D. and Voet, J., 1995).
		Chaperonins are ubiquitous and abundant proteins which form large, toroidal complexes.
	www.bio.cmu.edu /Courses/03441/TermPapers/96TermPapers/heat-shock/GroE.html (1314 words)

	Palaeos Bacteria: Glossary A-L
		Chaperonins also have a limited ability to "repair" proteins which have been incorrectly folded.
		Class II chaperonins are very closely related to Class I chaperonins by structure, but not by sequence.
		DnaK: a bacterial chaperonin homologous to the Hsp70 of eukaryotes.
	www.palaeos.com /Bacteria/Lists/Glossary/Gloss.html (2605 words)

	Altered protein orders metal bits TRN 122502
		Chaperonins are essential proteins that exist in nearly all organisms, said McMillan.
		Chaperonins are made of 14, 16 or 18 protein subunits arranged in a pair of stacked rings.
		These chaperonin crystals arranged 5-nanometer quantum dots into arrays when the researchers used the variant with the 3-nanometer opening, while the the 9-nanometer chaperonin arranged 10-nanometer quantum dots.
	www.trnmag.com /Stories/2003/010103/Altered_protein_orders_metal_bits_122502.html (1045 words)

	Chaperone rings in protein folding and degradation -- Horwich et al. 96 (20): 11033 -- Proceedings of the National ... (Site not responding. Last check: 2007-10-21)
		Protein folding chaperonins are illustrated in the upper portion of each "cell," and proteolytic chaperones and the associated proteolytic cylinders are shown in the lower portion.
		The apical peptide binding surfaces of helices H and I (arrows), as well as an underlying segment, are removed from facing the central cavity to a position rotated upward 60° and twisted 90° clockwise (see text and ref. 3 for details).
		This very stable complex is the longest-lived state of the chaperonin system in the presence of non-native polypeptide (63), and it is weakened and prepared for dissociation by hydrolysis in the cis ring, which allows entry of ATP and non-native polypeptide into the trans ring (30).
	www.pnas.org /cgi/content/full/96/20/11033 (6794 words)

	Expression of stress proteins and mitochondrial chaperonins in chronically stimulated skeletal muscle. (Site not responding. Last check: 2007-10-21)
		The purpose of the present study was to evaluate the relationship between mitochondrial content under steady-state conditions, and during the induction of organelle biogenesis, with the expression of stress proteins and mitochondrial chaperonins.
		Thus, the expression of individual mitochondrial chaperonins is independently regulated and uncoordinated.
		It remains to be determined whether this marked induction of proteins comprising part of the protein import machinery is beneficial for the translocation of enzyme precursors into the mitochondria during conditions of accelerated biogenesis.
	www.yorku.ca /dhood/Publctns/9510.htm (324 words)

	[No title]
		We are studying type I chaperonins, tetradecameric oligomeric proteins composed of 60 kDa subunits (cpn60) that work together with small heptameric ring-shaped helper proteins composed of 10 kDa (cpn10) subunits [9, 10].
		Mutants in a number of the plant chaperonins were shown to result in phenotypes ranging from stunted growth to lethality [22, 23].
		Levy-Rimler, G., Viitanen, P., Weiss, C., Sharkia, R., Greenberg, A., Niv, A., Lustig, A., Delarea, Y. and Azem, A. (2001) The effect of nucleotides and mitochondrial chaperonin 10 on the structure and chaperone activity of mitochondrial chaperonin 60, Eur J Biochem.
	www.tau.ac.il /lifesci/departments/biochem/members/azem/research.html (1580 words)

	ATP-Induced Shape Change in a Model Protein Complexed in Chaperonins
		Among the growing list of chaperone families are the chaperonins G r o E L (E L) and G r o E S (E S), which have been intensively studied.
		The ultimate goal is to determine the mechanism by which E L transforms its substrate proteins and then releases them in a form able to refold to their native conformation.
		One of the key issues in establishing a molecular mechanism for E L is to describe in structural terms the conformations of polypeptide substrates when bound to various chaperonin complexes.
	www.ncnr.nist.gov /AnnualReport/FY2003_html/RH9 (985 words)

	John M. Archibald, Roger Lab, Dalhousie University, Canada (Site not responding. Last check: 2007-10-21)
		The chaperonins are a class of evolutionarily related molecular chaperones that form multisubunit double-ring complexes and facilitate protein folding through the hydrolysis of ATP.
		Phylogenetic analyses of archaeal chaperonins reveal a complex pattern of lineage-specific gene duplication, gene conversion and gene loss, and suggest that hetero-oligomeric chaperonin complexes have evolved multiple times independently during the history of this group.
		In contrast, numerous chaperonin gene duplications occurred early in eukaryotic evolution and produced eight distinct paralogs, prior to the diversification of all eukaryotes under investigation.
	hades.biochem.dal.ca /Rogerlab/John/John.html (359 words)

	[No title] (Site not responding. Last check: 2007-10-21)
		It turns out that protein folding is not as simple as once thought, and that proteins called "chaperonins" are important in assisting that folding.
		To my mind, the action of chaperonins raises questions not only about "accepted wisdom" but about possible methods of use when we try to control such reactions ourselves.
		So long as their shapes remain stable under the conditions for which we design them, they need not be the only shapes our designed molecules can adopt.
	keithlynch.net /cryonet/9/91.html (1085 words)

	Chaperonins govern growth of Escherichia coli at low temperatures - Nature Biotechnology (Site not responding. Last check: 2007-10-21)
		Despite the fundamental importance of one (or at most two) cellular functions that determine the growth range of a cell or an organism, in most cases we have little idea of their identity.
		The question thus arises of whether the vital role of chaperonins is the function that determines the lower temperature limit of E.
		In vivo and in vitro properties of the chaperonins of Oleispira antarctica.
	www.nature.com /cgi-taf/DynaPage.taf?file=/nbt/journal/v21/n11/full/nbt1103-1266b.html (1046 words)

	Project4 (Site not responding. Last check: 2007-10-21)
		The molecular chaperonin TF55 from Sulfolobus solfataricus Chaperonins are high molecular weight complexes that form cage-like structures of two stacked homo- or hetero-oligomeric rings.
		The chaperonins in these organisms as well as in the eukaryotic cytosol belong to the so called t-complex polypeptide-1 (TCP1) family.
		It is notable that already at this low resolution level the degree of internal symmetry of the complex has been reduced from 9- to 3-fold as suggested by the plane group and the shape of the subunits.
	www.csb.ki.se /users/hans/project4.html (470 words)

	Crystal Structure Of The Archaeal Chaperonin Thermosome, A Protein-Folding Machine, Determined
		According to their general importance chaperonins are present in all three kingdoms of life: eubacteria, archaea and eukaryotes.
		Group II chaperonins are comprised of the archaeal chaperonins, e.g.
		The crystal structure of the thermosome provides clues for understanding the mode of action of group II chaperonins on a molecular basis, containing a built-in lid domain that substitutes for a cochaperonin.
	www.eurekalert.org /pub_releases/1998-04/M-CSOT-030498.php (391 words)

	Identification of in vivo substrates of the yeast mitochondrial chaperonins reveals overlapping but non-identical ... (Site not responding. Last check: 2007-10-21)
		Yeast rhodanese and malate dehydrogenase fold in the absence of chaperonins in vivo
		are the chaperonins from E.coli; hsp60 and hsp10 are the corresponding
		Hutchinson, J.P., El-Thaher, T.S.H. and Miller, A.D. Refolding and recognition of mitochondrial malate dehydrogenase by Escherichia coli chaperonins cpn60 (GroEL) and cpn10 (GroES).
	embojournal.npgjournals.com /cgi/content/full/17/20/5868 (6139 words)

	The chaperonin of the archaeon Sulfolobus solfataricus is an RNA-binding protein that participates in ribosomal RNA ... (Site not responding. Last check: 2007-10-21)
		The chaperonin of the archaeon Sulfolobus solfataricus is an RNA-binding protein that participates in ribosomal RNA processing -- Ruggero et al.
		The association between an rRNA and the chaperonin was of unclear significance.
		Kagawa, H.K., Osipiuk, J., Maltsev, N., Overbeek, R., Quaite-Randall, E., Joachimiak, A. and Trent, J.D. The heat shock proteins from a hyperthermophilic archaeon are related to the cytosolic chaperonin in eukaryotes.
	embojournal.npgjournals.com /cgi/content/full/17/12/3471 (4463 words)

	Chaperonin structure and conformational changes (Site not responding. Last check: 2007-10-21)
		Low resolution studies of chaperonins by EM The distinctive structure of cpn60 was observed in the 1970s by negative stain EM.
		Although they are both double ring complexes with 4 layers of density perpendicular to the symmetry axis, there are 7 subunits forming the rings in the eubacterial chaperonin and 8 in the eukaryotic cytosolic protein.
		In archaebacterial members of the TCP1 subfamily of chaperonins, there are 8 or 9 subunits in the ring (Phipps et al., 1991; Marco et al., 1994b).
	www.cryst.bbk.ac.uk /PPS2/course/section12/ellis.html (6291 words)

	BCMB513-2
		Chaperonins are divided into Group I or Group II based on the presence or absence of a co-chaperonin.
		Group I chaperonins include Hsp60 protiens (GroEL in bacteria, RBP in plants) And all consist of 14 identical 60,000MW subunits arranged in two stacked rings of seven subunits each.
		Group II chaperonins have two stacked octameric rings and have a larger central cavity than group one.
	www.bio.utk.edu /BCMB513-2/bcmb513-2.htm (2852 words)

	UPHS: News and Periodicals: (Site not responding. Last check: 2007-10-21)
		In times of stress, cells produce chaperonins, which are huge protein molecules that police other proteins that have misfolded as a result of any number of stressors -- including heat, heavy-metal poisoning, and ultraviolet radiation.
		In such misfolding disorders as mad cow's disease, chaperonins may fail to do their job correctly, but whether they come into play in the disease process is as yet unknown.
		This work was conducted in the Johnson Research Foundation, a funding and research organization within Penn's Department of Biochemistry and Biophysics that concentrates on the study of physics as it applies to medicine.
	www.uphs.upenn.edu /news/News_Releases/apr99/folding.shtml (563 words)

	Pfam 19.0 : Cpn10 (Site not responding. Last check: 2007-10-21)
		The chaperonins are 'helper' molecules required for correct folding and subsequent assembly of some proteins PUBMED:1349837.
		Type I chaperonins present in eubacteria, mitochondria and chloroplasts require the concerted action of 2 proteins, chaperonin 60 (cpn60) and chaperonin 10 (cpn10) PUBMED:12354603.
		The 10 kDa chaperonin (cpn10 - or groES in bacteria) exists as a ring-shaped oligomer of between six to eight identical subunits, while the 60 kDa chaperonin (cpn60 - or groEL in bacteria) forms a structure comprising 2 stacked rings, each ring containing 7 identical subunits PUBMED:2897629.
	pfam.wustl.edu /cgi-bin/getdesc?name=Cpn10 (377 words)

	Coexistence of Group I and Group II Chaperonins in the Archaeon Methanosarcina mazei -- Klunker et al. 278 (35): 33256 ...
		Coexistence of Group I and Group II Chaperonins in the Archaeon Methanosarcina mazei -- Klunker et al.
		Coexpression of group I and II chaperonins and their co-factors in the cytosol of M.
		At the times indicated, chaperonin activity was inhibited by the addition of CDTA and rhodanese activity determined at 25 °C. 100% corresponds to native enzyme control.
	www.jbc.org /cgi/content/full/278/35/33256 (5140 words)

Try your search on: Qwika (all wikis)