1
|
Delbecq SP, Klevit RE. One size does not fit all: the oligomeric states of αB crystallin. FEBS Lett 2013; 587:1073-80. [PMID: 23340341 DOI: 10.1016/j.febslet.2013.01.021] [Citation(s) in RCA: 126] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2012] [Revised: 01/09/2013] [Accepted: 01/10/2013] [Indexed: 11/25/2022]
Abstract
Small Heat Shock Proteins (sHSPs) are a diverse family of molecular chaperones that delay protein aggregation through interactions with non-native and aggregate-prone protein states. This function has been shown to be important to cellular viability and sHSP function/dysfunction is implicated in many diseases, including Alzheimer's and Alexander disease. Though their gene products are small, many sHSPs assemble into a distribution of large oligomeric states that undergo dynamic subunit exchange. These inherent properties present significant experimental challenges for characterizing sHSP oligomers. Of the human sHSPs, αB crystallin is a paradigm example of sHSP oligomeric properties. Advances in our understanding of sHSP structure, oligomeric distribution, and dynamics have prompted the proposal of several models for the oligomeric states of αB. The aim of this review is to highlight characteristics of αB crystallin (αB) that are key to understanding its structure and function. The current state of knowledge, existing models, and outstanding questions that remain to be addressed are presented.
Collapse
Affiliation(s)
- Scott P Delbecq
- Department of Biochemistry, Box 357350, University of Washington, Seattle, WA 98195-7350, USA
| | | |
Collapse
|
2
|
Karmakar S, Das KP. Identification of Histidine Residues Involved in Zn2+ Binding to αA- and αB-Crystallin by Chemical Modification and MALDI TOF Mass Spectrometry. Protein J 2012; 31:623-40. [DOI: 10.1007/s10930-012-9439-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
|
3
|
Chowdhury A, Mojumdar SS, Choudhury A, Banerjee R, Das KP, Sasmal DK, Bhattacharyya K. Deoxycholate induced tetramer of αA-crystallin and sites of phosphorylation: Fluorescence correlation spectroscopy and femtosecond solvation dynamics. J Chem Phys 2012; 136:155101. [DOI: 10.1063/1.3702810] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
|
4
|
Dickinson CD, Floener LA, Lilley GG, Nielsen NC. Self-assembly of proglycinin and hybrid proglycinin synthesized in vitro from cDNA. Proc Natl Acad Sci U S A 2010; 84:5525-9. [PMID: 16593868 PMCID: PMC298895 DOI: 10.1073/pnas.84.16.5525] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
An in vitro system was developed that results in the self-assembly of subunit precursors into complexes that resemble those found naturally in the endoplasmic reticulum. Subunits of glycinin, the predominant seed protein of soybeans, were synthesized from modified cDNAs using a combination of the SP6 transcription and the rabbit reticulocyte translation systems. Subunits produced from plasmid constructions that encoded either Gy4 or Gy5 gene products, but modified such that their signal sequences were absent, self-assembled into trimers equivalent in size to those precursors found in the endoplasmic reticulum. In contrast, proteins synthesized in vitro from Gy4 constructs failed to self-assemble when the signal sequence was left intact (e.g., preproglycinin) or when the coding sequence was modified to remove 27 amino acids from an internal hydrophobic region, which is highly conserved among the glycinin subunits. Various hybrid subunits were also produced by trading portions of Gy4 and Gy5 cDNAs and all self-assembled in our system. The in vitro assembly system provides an opportunity to study the self-assembly of precursors and to probe for regions important for assembly. It will also be helpful in attempts to engineer beneficial nutritional changes into this important food protein.
Collapse
Affiliation(s)
- C D Dickinson
- U.S. Department of Agriculture/Agricultural Research Service, Department of Agronomy, Purdue University, West Lafayette, IN 47907
| | | | | | | |
Collapse
|
5
|
Viner RI, Zhang T, Second T, Zabrouskov V. Quantification of post-translationally modified peptides of bovine alpha-crystallin using tandem mass tags and electron transfer dissociation. J Proteomics 2009; 72:874-85. [PMID: 19245863 DOI: 10.1016/j.jprot.2009.02.005] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2008] [Revised: 02/10/2009] [Accepted: 02/12/2009] [Indexed: 12/21/2022]
Abstract
The modification of Ser/Thr residues in proteins by addition of single O-linked N-acetylglucosamine (O-GlcNAc) moieties play an important role in cell regulation. However, understanding the cellular mechanisms that regulate O-GlcNAc glycosylation has been challenging due to the difficulty in detection and quantification of this modification. Mass spectrometry-based multiplex quantitative approaches have been successfully employed to measure relative phosphorylation levels using collisionally induced dissociation (CID). However, labile modifications such as O-GlcNAc are lost prior to fragmentation of the peptide backbone in conventional CID, often preventing correct peptide identification, localization of the modified site, and as a result, relative quantification. Compared to CID, Electron Transfer Dissociation (ETD) preserves labile post-translational modifications (PTMs), and allows direct mapping of peptide/protein modifications. This is the first report to assess the utility of combining multiplexed isobaric tandem mass tag (TMT) labeling and ETD for relative quantification of labile PTMs. ETD analysis of both labeled and unlabeled peptides from bovine alpha-crystallins pinpointed at least one O-GlcNAc containing modification site in each of the protein subunits, in addition to a multitude of other PTMs, including glycation, phosphorylation, and acetylation. Moreover, ETD of TMT(6) labeled peptides produced four unique reporter ions that could be used for relative quantification. TMT reporter ion ratios measured by ETD had similar accuracy and precision as those obtained by conventional CID techniques. When applied to glycosylated or otherwise modified peptides, ETD was the only dissociation method which consistently provided confident sequence identification, PTM localization, and quantitative information, all in the same spectrum. This suggests that ETD-based workflows can be complementary to traditional CID approaches when used for simultaneous qualitative and quantitative analysis of modified peptides.
Collapse
Affiliation(s)
- Rosa I Viner
- Thermo Fisher Scientific, 355 River Oaks Parkway, San Jose, CA 95134, USA
| | | | | | | |
Collapse
|
6
|
Engineering two mutants of cDNA-encoding G2 subunit of soybean glycinin capable of self-assembly in vitro and rich in methionine. Biologia (Bratisl) 2007. [DOI: 10.2478/s11756-007-0097-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
|
7
|
Geerlof A, Lewendon A, Shaw WV. Purification and characterization of phosphopantetheine adenylyltransferase from Escherichia coli. J Biol Chem 1999; 274:27105-11. [PMID: 10480925 DOI: 10.1074/jbc.274.38.27105] [Citation(s) in RCA: 96] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Phosphopantetheine adenylyltransferase (PPAT) catalyzes the penultimate step in coenzyme A (CoA) biosynthesis: the reversible adenylation of 4'-phosphopantetheine yielding 3'-dephospho-CoA and pyrophosphate. Wild-type PPAT from Escherichia coli was purified to homogeneity. N-terminal sequence analysis revealed that the enzyme is encoded by a gene designated kdtB, purported to encode a protein involved in lipopolysaccharide core biosynthesis. The gene, here renamed coaD, is found in a wide range of microorganisms, indicating that it plays a key role in the synthesis of 3'-dephospho-CoA. Overexpression of coaD yielded highly purified recombinant PPAT, which is a homohexamer of 108 kDa. Not less than 50% of the purified enzyme was found to be associated with CoA, and a method was developed for its removal. A steady state kinetic analysis of the reverse reaction revealed that the mechanism of PPAT involves a ternary complex of enzyme and substrates. Since purified PPAT lacks dephospho-CoA kinase activity, the two final steps of CoA biosynthesis in E. coli must be catalyzed by separate enzymes.
Collapse
Affiliation(s)
- A Geerlof
- Department of Microbiology and Immunology, University of Leicester, Leicester LE1 9HN, United Kingdom.
| | | | | |
Collapse
|
8
|
Kokke BP, Leroux MR, Candido EP, Boelens WC, de Jong WW. Caenorhabditis elegans small heat-shock proteins Hsp12.2 and Hsp12.3 form tetramers and have no chaperone-like activity. FEBS Lett 1998; 433:228-32. [PMID: 9744800 DOI: 10.1016/s0014-5793(98)00917-x] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Four 12.2-12.6 kDa small heat-shock proteins (sHSPs) of Caenorhabditis elegans are the smallest known members of the sHSP family. They essentially comprise the characteristic C-terminal 'alpha-crystallin domain' of the sHSPs, having a very short N-terminal region, and lacking a C-terminal tail. Recombinant Hsp12.2 and 12.3 are characterized here. Far-UV CD spectra reveal, as for other sHSPs, predominantly a beta-sheet structure. By gel permeation and crosslinking, they are the first sHSPs shown to occur as tetramers, rather than forming the usual large multimeric complexes. Exceptionally, too, both appear devoid of in vitro chaperone-like abilities. This supports the notion that tetramers are the building blocks of sHSP complexes, and that higher multimer formation, mediated through the N-terminal domains, is a prerequisite for chaperone-like activity.
Collapse
Affiliation(s)
- B P Kokke
- Department of Biochemistry, University of Nijmegen, The Netherlands
| | | | | | | | | |
Collapse
|
9
|
Leroux MR, Melki R, Gordon B, Batelier G, Candido EP. Structure-function studies on small heat shock protein oligomeric assembly and interaction with unfolded polypeptides. J Biol Chem 1997; 272:24646-56. [PMID: 9305934 DOI: 10.1074/jbc.272.39.24646] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
The small heat shock protein (smHSP) and alpha-crystallin genes encode a family of 12-43-kDa proteins which assemble into large multimeric structures, function as chaperones by preventing protein aggregation, and contain a conserved region termed the alpha-crystallin domain. Here we report on the structural and functional characterization of Caenorhabditis elegans HSP16-2, a 16-kDa smHSP produced only under stress conditions. A combination of sedimentation velocity, size exclusion chromatography, and cross-linking analyses on wild-type HSP16-2 and five derivatives demonstrate that the N-terminal domain but not most of the the C-terminal extension which follows the alpha-crystallin domain is essential for the oligomerization of the smHSP into high molecular weight complexes. The N terminus of HSP16-2 is found to be buried within complexes which can accommodate at least an additional 4-kDa of heterologous sequence per subunit. Studies on the interaction of HSP16-2 with fluorescently-labeled and radiolabeled actin and tubulin reveal that this smHSP possesses a high affinity for unfolded intermediates which form early on the aggregation pathway, but has no apparent substrate specificity. Furthermore, both wild-type and C-terminally-truncated HSP16-2 can function as molecular chaperones by suppressing the thermally-induced aggregation of citrate synthase. Taken together, our data on HSP16-2 and a unique 12.6-kDa smHSP we have recently characterized demonstrate that multimerization is a prerequisite for the interaction of smHSPs with unfolded protein as well as for chaperone activity.
Collapse
Affiliation(s)
- M R Leroux
- Department of Biochemistry and Molecular Biology, University of British Columbia, Vancouver, British Columbia, V6T 1Z3 Canada
| | | | | | | | | |
Collapse
|
10
|
Abstract
Alpha crystallin can function as a molecular chaperone in suppressing the heat-induced aggregation of other crystallins and proteins. During cataractogenesis, alpha-crystallin becomes a water-insoluble, high-molecular-weight, cross-linked aggregate. To determine whether the chaperone activity of alpha crystallin is lost during this age-related modification, extracts were prepared by sonication of water-insoluble proteins isolated from aged bovine lenses and human cataract lenses. All the preparations were tested for chaperone-like activity using beta L-crystallin as the target protein and the percentage of alpha-crystallin in water-insoluble sonicated supernatant (WISS) was determined by slot blot immunoassay. The WISS from bovine as well as human lenses were still effective in protecting beta L-crystallin aggregation at 56 degrees C. The bovine cortical WISS with 50% immunoreactive alpha-crystallin showed 62% of the chaperone-like activity displayed by native alpha-crystallin. The WISS from bovine lens nucleus and human lenses with 17% and 5% immunoreactive alpha-crystallin showed 19% and 4% chaperone-like activity compared to native alpha-crystallin. Prior treatment of the WISS of both bovine and human lenses with dithiothreitol resulted in nearly 50% increase in chaperone-like activity suggesting possible loss of chaperone-like activity due to disulfide cross-links. To see if the chaperone-like activity of alpha-crystallin can be altered by non-disulfide cross-linking, native alpha-crystallin isolated from bovine lenses was cross-linked with dimethylsuberimidate (DMS) and dimethyl 3,3'-dithiobispropionimidate (DTBP) and tested for chaperone-like activity. The DMS cross-linked alpha-crystallin was effective in inhibiting the aggregation of beta L-crystallins at 56 degrees C, but required a two- to five-fold higher concentration than the native alpha-crystallin. alpha-Crystallin with higher degree of cross-linking showed lower chaperone-like activity. alpha-Crystallin cross-linked with DTBP, a cleavable cross-linking agent, also showed a 80% loss in chaperone-like activity. However, when the DTBP cross-linked alpha-crystallin was treated with dithiothreitol to cleave the cross-links there was a 50% recovery in the chaperone-like activity. These data suggest that the age-related cross-linking, which restricts the molecular flexibility of alpha-crystallin decreases its chaperone-like function.
Collapse
Affiliation(s)
- K K Sharma
- Mason Institute of Ophthalmology, University of Missouri, Columbia 65212, USA
| | | |
Collapse
|
11
|
Groenen PJ, Merck KB, de Jong WW, Bloemendal H. Structure and modifications of the junior chaperone alpha-crystallin. From lens transparency to molecular pathology. EUROPEAN JOURNAL OF BIOCHEMISTRY 1994; 225:1-19. [PMID: 7925426 DOI: 10.1111/j.1432-1033.1994.00001.x] [Citation(s) in RCA: 282] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
alpha-Crystallin is a high-molecular-mass protein that for many decades was thought to be one of the rare real organ-specific proteins. This protein exists as an aggregate of about 800 kDa, but its composition is simple. Only two closely related subunits termed alpha A- and alpha B-crystallin, with molecular masses of approximately 20 kDa, form the building blocks of the aggregate. The idea of organ-specificity had to be abandoned when it was discovered that alpha-crystallin occurs in a great variety of nonlenticular tissues, notably heart, kidney, striated muscle and several tumors. Moreover alpha B-crystallin is a major component of ubiquinated inclusion bodies in human degenerative diseases. An earlier excitement arose when it was found that alpha B-crystallin, due to its very similar structural and functional properties, belongs to the heat-shock protein family. Eventually the chaperone nature of alpha-crystallin could be demonstrated unequivocally. All these unexpected findings make alpha-crystallin a subject of great interest far beyond the lens research field. A survey of structural data about alpha-crystallin is presented here. Since alpha-crystallin has resisted crystallization, only theoretical models of its three-dimensional structure are available. Due to its long life in the eye lens, alpha-crystallin is one of the best studied proteins with respect to post-translational modifications, including age-induced alterations. Because of its similarities with the small heat-shock proteins, the findings about alpha-crystallin are illuminative for the latter proteins as well. This review deals with: structural aspects, post-translational modifications (including deamidation, racemization, phosphorylation, acetylation, glycation, age-dependent truncation), the occurrence outside of the eye lens, the heat-shock relation and the chaperone activity of alpha-crystallin.
Collapse
Affiliation(s)
- P J Groenen
- Department of Biochemistry, University of Nijmegen, The Netherlands
| | | | | | | |
Collapse
|
12
|
Merck KB, De Haard-Hoekman WA, Oude Essink BB, Bloemendal H, De Jong WW. Expression and aggregation of recombinant alpha A-crystallin and its two domains. BIOCHIMICA ET BIOPHYSICA ACTA 1992; 1130:267-76. [PMID: 1562604 DOI: 10.1016/0167-4781(92)90439-7] [Citation(s) in RCA: 97] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The 20 kDa alpha A and alpha B subunits of alpha-crystallin from mammalian eye lenses form large aggregates with an average molecular weight of 800,000. To get insight into the interactions responsible for aggregate formation, we expressed in Escherichia coli the putative N- and C-terminal domains of alpha A-crystallin, as well as the intact alpha A-crystallin chain. The proteins are expressed in a stable form and in relatively high amounts (20-60% of total protein). Recombinant alpha A-crystallin and the C-terminal domain are expressed in a water-soluble form. Recombinant alpha A-crystallin forms aggregates comparable with alpha-crystallin aggregates from calf lenses, whereas the C-terminal domain forms dimers or tetramers. The N-terminal domain is expressed in an initially water-insoluble form. After solubilization, denaturation and reaggregation the N-terminal domain exists in a high molecular weight multimeric form. These observations suggest that the interactions leading to aggregation of alpha A-crystallin subunits are mainly located in the N-terminal half of the chain.
Collapse
Affiliation(s)
- K B Merck
- Department of Biochemistry, University of Nijmegen, Netherlands
| | | | | | | | | |
Collapse
|
13
|
Rapp WD, Lilley GG, Nielsen NC. Characterization of soybean vegetative storage proteins and genes. TAG. THEORETICAL AND APPLIED GENETICS. THEORETISCHE UND ANGEWANDTE GENETIK 1990; 79:785-792. [PMID: 24226740 DOI: 10.1007/bf00224246] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/06/1989] [Accepted: 01/22/1990] [Indexed: 06/02/2023]
Abstract
Soybean vegetative storage proteins (VSPs) were purified and characterized. Anion exchange HPLC resolved partially purified VSPs into fractions containing 27-kD/27-kD and 29-kD/29-kD homodimers and 27-kD/29-kD heterodimers. Reversed-phase HPLC resolved partially purified VSPs into three fractions. One fraction contained only 27-kD VSP and the other two contained 29-kD VSP. The two 29-kD VSP fractions differed with respect to their cyanogen bromide cleavage patterns, an observation that indicated the 29-kD VSPs were heterogeneous. Genomic clones that contained 29-kD VSP genes were also isolated and characterized. One genomic clone contained a complete 29-kD VSP gene and was sequenced. The coding region in the clone contained two introns whose borders had regulatory sequences typical of other eukaryotic genes. Putative polyadenlyation signals were present in the 3'-flanking region of the gene, while putative TATA, CAAT, and enhancer core sequences were found in the 5'-flanking regions. A second genomic clone that was studied contained the 5' regions of two partial 29-kD VSP genes in an inverted linkage. Genomic DNA gel blots showed that the two genes were organized in the same arrangement in the soybean genome.
Collapse
Affiliation(s)
- W D Rapp
- USDA/Agricultural Research Service and the Department of Agronomy, Purdue University, 47907, West Lafayette, IN, USA
| | | | | |
Collapse
|
14
|
Ravid K, Rosenthal RA, Doctrow SR, Lowenstein JM. 28 kDa adenosine-binding proteins of brain and other tissues. Biochem J 1989; 258:653-61. [PMID: 2730563 PMCID: PMC1138416 DOI: 10.1042/bj2580653] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
Membranes prepared from calf brain were solubilized and chromatographed on a column containing 5'-amino-5'-deoxyadenosine covalently linked to agarose through the 5'-amino group. When the column was eluted with adenosine, a pure protein emerged with subunit molecular mass of 28 kDa. The protein was extracted from the membranes with sodium cholate, but not with 100 microM-adenosine or 0.5 M-NaCl. A similar 28 kDa protein was isolated from the soluble fraction of calf brain. The yield of membrane-bound and soluble 28 kDa protein per gram of tissue was about the same. The 28 kDa protein was also found in membrane and soluble fractions of rabbit heart, rat liver and vascular smooth muscle from calf aorta. The yield per gram of tissue fell into the order brain greater than heart approximately vascular smooth muscle greater than liver for the 28 kDa protein from the membrane fraction, and brain approximately heart greater than vascular smooth muscle greater than liver for the 28 kDa protein from the soluble fraction. Polyclonal antibodies to pure 28 kDa protein from calf brain membranes cross-reacted with the 28 kDa protein from calf brain soluble fraction and with 28 kDa proteins isolated from other tissues. The 28 kDa protein from calf brain membranes was also eluted from the affinity column by AMP and 2',5'-dideoxyadenosine, but at a concentration higher than that at which adenosine eluted the protein, but N6-(R-phenylisopropyl)adenosine, 5'-N-ethylcarboxamidoadenosine, ADP, ATP, GTP, NAD+, cyclic AMP and inosine failed to elute the protein at concentrations up to 1 mM. The 28 kDa protein from the soluble fraction was not eluted by 3 mM-AMP or 1 mM-N6-(R-phenylisopropyl)adenosine,-5'-N-ethylcarboxamidoadenosine or -cyclic AMP. Unexpectedly, the soluble 28 kDa protein was eluted by AMP in the presence of sodium cholate. Soluble 28 kDa protein from calf brain had a KD for adenosine of 12 microM. Membrane 28 kDa protein from calf brain had a KD of 14 microM in the presence of 0.1% sodium cholate. Amino acid compositions of the 28 kDa proteins were similar, but not identical.
Collapse
Affiliation(s)
- K Ravid
- Graduate Department of Biochemistry, Brandeis University, Waltham, MA 02254
| | | | | | | |
Collapse
|
15
|
Siezen RJ, Coppin CM, Benedek GB. Permanent suppression of phase separation cataract in calf lens using amine modification agents. Biochem Biophys Res Commun 1985; 133:239-47. [PMID: 4074365 DOI: 10.1016/0006-291x(85)91867-4] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Low temperature induced opacification (cold cataract) of the nucleus of young mammalian lenses is associated with a phase separation of proteins in the lens cell cytoplasm. Calf lenses were treated with a variety of imido-esters and N-hydroxysuccinimide-esters, which react specifically with amino groups. Many potent inhibitors of phase separation cataract were identified which lower the opacification temperature by 6 degrees C or more. Lenses generally remain clear, colorless and soft. Furthermore, suppression of the cold cataract temperature is permanent upon removal of excess reagent.
Collapse
|
16
|
Bindels JG, Misdom LW, Hoenders HJ. The reaction of citraconic anhydride with bovine alpha-crystallin lysine residues. Surface probing and dissociation-reassociation studies. BIOCHIMICA ET BIOPHYSICA ACTA 1985; 828:255-60. [PMID: 3921054 DOI: 10.1016/0167-4838(85)90305-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Citraconic anhydride reacts readily with alpha-crystallin's lysine residues at pH 7.4. Upon addition of 2 equivalents of citraconic anhydride per equivalent lysine, 24% of the lysine residues were modified without disrupting the native quaternary structure. Further citraconylation led to dissociation into 10 S aggregates. Complete dissociation into subunits (1.4 S) occurred after adding 100 equivalents of citraconic anhydride, resulting in 98% modification. Decitraconylation did not lead to reaggregates identical with the native ones. The unmodified and the once and twice citraconylated alpha-crystallin subunits were discerned by isoelectric focusing according to their theoretical isoelectric points. In the native alpha-crystallin aggregates, nearly all B chains and approx. 60% of the A chains were found to possess at least one surface-exposed lysine residue. No differences between the susceptibilities to citraconylation of the in vivo deamidated (A1 and B1) and the de novo synthesized (A2 and B2) subunits were found. These results support the three-layer spherical assembly model for the alpha-crystallin quaternary structure.
Collapse
|
17
|
Blagrove RJ, Lilley GG, Van Donkelaar A, Sun SM, Hall TC. Structural studies of a french bean storage protein: phaseolin. Int J Biol Macromol 1984. [DOI: 10.1016/0141-8130(84)90054-0] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
|
18
|
Sculley MJ, Treacy OB, Jeffrey PD. A new theoretical approach to the investigation of the symmetry of protein oligomers with bifunctional reagents. Biophys Chem 1984; 19:39-47. [PMID: 17005131 DOI: 10.1016/0301-4622(84)85004-8] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/1983] [Accepted: 09/13/1983] [Indexed: 11/22/2022]
Abstract
The use of bifunctional reagents to form cross-links between subunits in protein oligomers and subsequent disruption of noncovalent interactions with SDS allows comment upon the number of subunits and the symmetry in the original assembly. In existing treatments the number of equations needed to describe theoretically the proportions of all the cross-linked species that can be formed as a function of time in this way makes the analysis of the system unmanageable for proteins with more than four subunits. A method is presented that allows the required equations for any oligomer to be formulated as an algorithm suitable for solution by computer. Its application is illustrated with reference to experimental results obtained with two protein hexamers, Jasus hemocyanin and alpha-urease from jack bean.
Collapse
Affiliation(s)
- M J Sculley
- Department of Physical Biochemistry, John Curtin School of Medical Research, Australian National University, Canberra, ACT 2601, Australia
| | | | | |
Collapse
|
19
|
Simonneau L, Hervé B, Jacquemin E, Courtois Y. State of differentiation of bovine epithelial lens cells in vitro. Modulation of the synthesis and of the polymerization of specific proteins (crystallins) and non-specific proteins in relation to cell divisions. Exp Cell Res 1983; 145:433-46. [PMID: 6407854 DOI: 10.1016/0014-4827(83)90022-8] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Maintenance of the state of differentiation in serially cultured bovine epithelial lens cells has been investigated. The radioactive labelled soluble proteins were studied by gel filtration and gel electrophoresis. 1. In the lens epithelium on its capsule, preferential synthesis of alpha B2 vs alpha A2 crystallin subunits and synthesis of beta-crystallins (mainly beta Bp) were observed. 2. Epithelial lens cells cultured on plastic Petri dishes for up to 35 divisions still synthesized alpha B2 and beta Bp, but no longer alpha A2. Conversely, the same cells injected into nude mice synthesized alpha B and alpha A, but no beta-crystallin could be detected. 3. The ratio of non-crystallin proteins to crystallin polypeptides increased drastically with the number of cell divisions. Among these proteins, both Mr 45 000 and Mr 57 000 proteins are probably constituents of the water-soluble cytoskeletal proteins, respectively actin and vimentin. A Mr 17 000 polypeptide was observed and its relationship with a metabolic product of alpha-crystallin is proposed. 4. The polymerization process of crystallin polypeptides in these cells was studied and compared with crystallin aggregates found in the lens. Newly synthesized alpha crystallins were readily involved in high molecular aggregates. This process does not seem to require alpha A, since only alpha B was detected. Interestingly, non-crystallin-soluble proteins form the bulk of proteins found in high molecular weight (HMW) polymers. The time course of crystallin aggregate formation, in long-term culture cells, seems to be different for alpha- vs beta-polypeptides. These results allowed us to conclude that bovine epithelial lens cells in vitro, although they do not undergo terminal differentiation into fibers, are not dedifferentiated, since they still express specific features of the epithelium in situ.
Collapse
|
20
|
Siezen RJ, Bindels JG. Stepwise dissociation/denaturation and reassociation/renaturation of bovine alpha-crystallin in urea and guanidine hydrochloride: sedimentation, fluorescence, near-ultraviolet and far-ultraviolet circular dichroism studies. Exp Eye Res 1982; 34:969-83. [PMID: 7084353 DOI: 10.1016/0014-4835(82)90077-x] [Citation(s) in RCA: 53] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
|
21
|
Randall J, Vaughan JM. The measurement and interpretation of Brillouin scattering in the lens of the eye. PROCEEDINGS OF THE ROYAL SOCIETY OF LONDON. SERIES B, BIOLOGICAL SCIENCES 1982; 214:449-70. [PMID: 6127691 DOI: 10.1098/rspb.1982.0021] [Citation(s) in RCA: 30] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Brillouin scattering from hypersonic waves in the eye lenses of many animals has been observed with a multipass Fabry Perot interferometer. The measured values of speed and attenuation range widely among the different species and in different parts of any one lens. These variations correlate broadly with the observed stiffness and the densities that have been measured with a graded column. From the spectroscopic and density measurements high-frequency elastic moduli may be derived. The results are also evaluated at a macromolecular level in terms of scattering of hypersonic waves from spherical entities composed of the crystallins and their aggregates. Reasonable agreement is obtained for the hypersonic speed for lower protein concentration; the hypersonic attenuation and variation with scattering vector are consistent with the presence of large aggregates (of order 100 nm radius) in certain of the materials.
Collapse
|
22
|
Siezen RJ, Bindels JG, Hoenders HJ. The quaternary structure of bovine alpha-crystallin. Effects of variation in alkaline pH, ionic strength, temperature and calcium ion concentration. EUROPEAN JOURNAL OF BIOCHEMISTRY 1980; 111:435-44. [PMID: 7460906 DOI: 10.1111/j.1432-1033.1980.tb04958.x] [Citation(s) in RCA: 101] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
The stability of the native quaternary structure of bovine alpha-crystallin was studied, by sedimentation analysis and electron microscopy, as a function of pH (7--11), ionic strength (0.01--0.5), temperature (6--60 degrees C) and calcium ion concentration (0 and 10 mM). Three successive transitions are distinguished at 20 degrees C. Firstly, a slow transconformation step, which is independent of pH, ionic strength or calcium ions. Secondly, an irreversible primary dissociation step, favoured by increasing pH above 8 and/or a lower ionic strength, with formation of 'alkali-modified alpha-crystallin', which is spherically shaped like the native protein but has a smaller average diameter, sedimentation coefficient and molecular weight. Thirdly, with further increase of pH above 9, a rapidly reversible dissociation of alkali-modified alpha-crystallin characterized by a single reaction boundary in sedimentation velocity analysis. In the presence of calcium ions the quaternary structure is stabilized to the extent that no dissociation is observed up to at least pH 10.3. Upon increase of temperature, at pH 7.3, a slow irreversible dissociation and swelling run parallel until a limit is reached around 37 degrees C with formation of 'temperature-modified alpha-crystallin', which is indistinguishable from the native protein by electron microscopy, but has a higher relative viscosity and lower sedimentation coefficient and molecular weight. Calcium ions have little or no effect on this transition. Above 37 degrees C a reversal of this transition or aggregation is indicated. These findings, together with previous structural data on microheterogeneity, reassociation from urea, and aging of alpha-crystallin in vivo, are incorporated into a hypothetical scheme of transitions, based on a three-layer model for the quaternary structure.
Collapse
|