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McCullough RW. High-potency sucralfate prevents and rapidly reverses chemo-radiation mucositis in a patient with stage 4b head and neck cancer. World J Transl Med 2013; 2:13-21. [DOI: 10.5528/wjtm.v2.i2.13] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2012] [Accepted: 04/27/2013] [Indexed: 02/05/2023] Open
Abstract
AIM: To study usefulness of high-potency sucralfate (HPS) in a patient with chemoradiation mucositis and discuss its mechanism of action.
METHODS: HPS, a non-covalently cross-link of sucralfate, cations and bidentate anionic chelators, has a maintains a surface concentration of sucralfate 3 h following administration that is 7-23 fold that possible with standard-potency sucralfate. The accelerated mucosal healing and pain alleviation of HPS in patients with erosive esophageal reflux, prompted its use in this patient with chemoradiation mucositis of the oropharynx and alimentary tract. A literature-based review of the immuno-modulatory effects of sucralfate is discussed.
RESULTS: Within 48 h of intervention: (1) there was complete disappearance of oral mucositis lesions; tenderness with (2) patient-reported disappearance of pain, nausea and diarrhea; patient required (3) no opiate analgesia and (4) no tube-feeding supplements to regular diet. Dysgeusia and xerostomia persisted. A modified Naranjo Questionnaire score of 10 supported the likelihood that HPS intervention caused the observed clinical effects. No adverse reactions noted.
CONCLUSION: In this patient HPS was useful to treat chemo-radiation mucositis of the oropharynx and alimentary tract. HPS may directly or indirectly facilitate an immunomodulatory mechanism involving accelerated growth factor activation, which may be a new target for therapeutic intervention in such patients.
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2
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Uversky VN. The alphabet of intrinsic disorder: II. Various roles of glutamic acid in ordered and intrinsically disordered proteins. INTRINSICALLY DISORDERED PROTEINS 2013; 1:e24684. [PMID: 28516010 PMCID: PMC5424795 DOI: 10.4161/idp.24684] [Citation(s) in RCA: 68] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/21/2013] [Revised: 03/27/2013] [Accepted: 04/12/2013] [Indexed: 11/19/2022]
Abstract
The ability of a protein to fold into unique functional state or to stay intrinsically disordered is encoded in its amino acid sequence. Both ordered and intrinsically disordered proteins (IDPs) are natural polypeptides that use the same arsenal of 20 proteinogenic amino acid residues as their major building blocks. The exceptional structural plasticity of IDPs, their capability to exist as heterogeneous structural ensembles and their wide array of important disorder-based biological functions that complements functional repertoire of ordered proteins are all rooted within the peculiar differential usage of these building blocks by ordered proteins and IDPs. In fact, some residues (so-called disorder-promoting residues) are noticeably more common in IDPs than in sequences of ordered proteins, which, in their turn, are enriched in several order-promoting residues. Furthermore, residues can be arranged according to their “disorder promoting potencies,” which are evaluated based on the relative abundances of various amino acids in ordered and disordered proteins. This review continues a series of publications on the roles of different amino acids in defining the phenomenon of protein intrinsic disorder and concerns glutamic acid, which is the second most disorder-promoting residue.
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Affiliation(s)
- Vladimir N Uversky
- Department of Molecular Medicine and USF Health Byrd Alzheimer's Research Institute; College of Medicine; University of South Florida; Tampa, FL USA.,Institute for Biological Instrumentation; Russian Academy of Sciences; Moscow, Russia
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Kannan R, Sreekumar PG, Hinton DR. Novel roles for α-crystallins in retinal function and disease. Prog Retin Eye Res 2012; 31:576-604. [PMID: 22721717 DOI: 10.1016/j.preteyeres.2012.06.001] [Citation(s) in RCA: 89] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 05/31/2012] [Accepted: 06/04/2012] [Indexed: 01/18/2023]
Abstract
α-Crystallins are key members of the superfamily of small heat shock proteins that have been studied in detail in the ocular lens. Recently, novel functions for α-crystallins have been identified in the retina and in the retinal pigmented epithelium (RPE). αB-Crystallin has been localized to multiple compartments and organelles including mitochondria, golgi apparatus, endoplasmic reticulum and nucleus. α-Crystallins are regulated by oxidative and endoplasmic reticulum stress, and inhibit apoptosis-induced cell death. α-Crystallins interact with a large number of proteins that include other crystallins, and apoptotic, cytoskeletal, inflammatory, signaling, angiogenic, and growth factor molecules. Studies with RPE from αB-crystallin deficient mice have shown that αB-crystallin supports retinal and choroidal angiogenesis through its interaction with vascular endothelial growth factor. αB-Crystallin has also been shown to have novel functions in the extracellular space. In RPE, αB-crystallin is released from the apical surface in exosomes where it accumulates in the interphotoreceptor matrix and may function to protect neighboring cells. In other systems administration of exogenous recombinant αB-crystallin has been shown to be anti-inflammatory. Another newly described function of αB-crystallin is its ability to inhibit β-amyloid fibril formation. α-Crystallin minichaperone peptides have been identified that elicit anti-apoptotic function in addition to being efficient chaperones. Generation of liposomal particles and other modes of nanoencapsulation of these minipeptides could offer great therapeutic advantage in ocular delivery for a wide variety of retinal degenerative, inflammatory and vascular diseases including age-related macular degeneration and diabetic retinopathy.
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Affiliation(s)
- Ram Kannan
- Arnold and Mabel Beckman Macular Research Center, Doheny Eye Institute, Los Angeles, CA 90033, United States
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4
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Conrad AH, Zhang Y, Tasheva ES, Conrad GW. Proteomic analysis of potential keratan sulfate, chondroitin sulfate A, and hyaluronic acid molecular interactions. Invest Ophthalmol Vis Sci 2010; 51:4500-15. [PMID: 20375348 DOI: 10.1167/iovs.09-4914] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
PURPOSE Corneal stroma extracellular matrix (ECM) glycosaminoglycans (GAGs) include keratan sulfate (KS), chondroitin sulfate A (CSA), and hyaluronic acid (HA). Embryonic corneal keratocytes and sensory nerve fibers grow and differentiate according to chemical cues they receive from the ECM. This study asked which of the proteins that may regulate keratocytes or corneal nerve growth cone immigration interact with corneal GAGs. METHODS Biotinylated KS (bKS), CSA (bCSA), and HA (bHA) were prepared and used in microarray protocols to assess their interactions with 8268 proteins and a custom microarray of 85 extracellular epitopes of nerve growth-related proteins. Surface plasmon resonance (SPR) was performed with bKS and SLIT2, and their ka, kd, and KD were determined. RESULTS Highly sulfated KS interacted with 217 microarray proteins, including 75 kinases, several membrane or secreted proteins, many cytoskeletal proteins, and many nerve function proteins. CSA interacted with 24 proteins, including 10 kinases and 2 cell surface proteins. HA interacted with 6 proteins, including several ECM-related structural proteins. Of 85 ECM nerve-related epitopes, KS bound 40 proteins, including SLIT, 2 ROBOs, 9 EPHs, 8 Ephrins (EFNs), 8 semaphorins (SEMAs), and 2 nerve growth factor receptors. CSA bound nine proteins, including ROBO2, 2 EPHs, 1 EFN, two SEMAs, and netrin 4. HA bound no ECM nerve-related epitopes. SPR confirmed that KS binds SLIT2 strongly. The KS core protein mimecan/osteoglycin bound 15 proteins. CONCLUSIONS Corneal stromal GAGs bind, and thus could alter the availability or conformation of, many proteins that may influence keratocyte and nerve growth cone behavior in the cornea.
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Affiliation(s)
- Abigail H Conrad
- Division of Biology, Kansas State University, Manhattan, Kansas 66506-4901, USA.
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5
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Anbazhagan V, Wang HM, Lu CS, Yu C. A residue-level investigation of the equilibrium unfolding of the C2A domain of synaptotagmin 1. Arch Biochem Biophys 2009; 490:158-62. [DOI: 10.1016/j.abb.2009.08.018] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2009] [Revised: 08/26/2009] [Accepted: 08/26/2009] [Indexed: 10/20/2022]
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6
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Ryu K, Kim CW, Kim BH, Han KS, Kim KH, Choi SI, Seong BL. Assessment of substrate-stabilizing factors for DnaK on the folding of aggregation-prone proteins. Biochem Biophys Res Commun 2008; 373:74-9. [DOI: 10.1016/j.bbrc.2008.05.186] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2008] [Accepted: 05/30/2008] [Indexed: 10/22/2022]
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7
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Rajalingam D, Graziani I, Prudovsky I, Yu C, Kumar TKS. Relevance of partially structured states in the non-classical secretion of acidic fibroblast growth factor. Biochemistry 2007; 46:9225-38. [PMID: 17636870 PMCID: PMC3656169 DOI: 10.1021/bi7002586] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Acidic fibroblast growth factor (aFGF) is a signal peptide-less protein that is secreted into the extracellular compartment as part of a multiprotein release complex, consisting of aFGF, S100A13 (a calcium binding protein), and a 40 kDa (p40) form of synaptotagmin (Syt1), a protein that participates in the docking of a variety of secretory vesicles. p40 Syt1, and specifically its C2A domain, is believed to play a major role in the non-classical secretion of the aFGF release complex mediated by the interaction of aFGF and p40 Syt1with the phospholipids of the cell membrane inner leaflet. In the present study, we investigate the structural characteristics of aFGF and the C2A domain of p40 Syt1 under acidic conditions, using a variety of biophysical techniques including multidimensional NMR spectroscopy. Urea-induced equilibrium unfolding (at pH 3.4) of both aFGF and the C2A domain are non-cooperative and proceed with the accumulation of stable intermediate states. 1-Anilino-8-napthalene sulfonate (ANS) binding and size-exclusion chromatography results suggest that both aFGF and the C2A domain exist as partially structured states under acidic conditions (pH 3.4). Limited trypsin digestion analysis and 1H-15N chemical shift perturbation data reveal that the flexibility of certain portions of the protein backbone is increased in the partially structured state(s) of aFGF. The residues that are perturbed in the partially structured state(s) in aFGF are mostly located at the N- and C-terminal ends of the protein. In marked contrast, most of the interactions stabilizing the native secondary structure are preserved in the partially structured state of the C2A domain. Isothermal titration calorimetry data indicate that the binding affinity between aFGF and the C2A domain is significantly enhanced at pH 3.4. In addition, both aFGF and the C2A domain exhibit much higher lipid binding affinity in their partially structured states. The translocation of the multiprotein FGF release complex across the membrane appears to be facilitated by the formation of partially structured states of aFGF and the C2A domain of p40 Syt1.
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Affiliation(s)
| | - Irene Graziani
- Department of Chemistry and Biochemistry, Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Igor Prudovsky
- Department of Chemistry and Biochemistry, Center for Molecular Medicine, Maine Medical Center Research Institute, Scarborough, Maine 04074
| | - Chin Yu
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
- Department of Chemistry, National Tsing Hua University, Hsinchu 30043, Taiwan
- To whom correspondence should be addressed. Phone: 479-575-5646. Fax: 479-575-4049. (T.K.S.K.). Phone: 886-35-711082. Fax: 886-35-721524. cyu@ mx.nthu.edu.tw (C.Y.)
| | - Thallapuranam Krishnaswamy S. Kumar
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701
- To whom correspondence should be addressed. Phone: 479-575-5646. Fax: 479-575-4049. (T.K.S.K.). Phone: 886-35-711082. Fax: 886-35-721524. cyu@ mx.nthu.edu.tw (C.Y.)
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8
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Fan H, Li H, Zhang M, Middaugh CR. Effects of Solutes on Empirical Phase Diagrams of Human Fibroblast Growth Factor 1. J Pharm Sci 2007; 96:1490-503. [PMID: 17094138 DOI: 10.1002/jps.20796] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
A variety of solutes are commonly used to increase the stability of protein in therapeutic formulations. An empirical phase diagram approach is used to evaluate the effects of different types of additives on the solution behavior of a protein of pharmaceutical interest, human fibroblast growth factor 1 (FGF-1). A specific stabilizer, heparin, and a nonspecific stabilizer, sucrose, were used in this work. The protein was characterized as a function of pH (3-8) and temperature (10-85 degrees C) using Far-UV circular dichroism (Far-UV CD), intrinsic and extrinsic fluorescence as well as second derivative UV absorption spectroscopy. Empirical phase diagrams were constructed to summarize the biophysical characterization data obtained with FGF-1 alone, in the presence of a threefold weight excess of heparin (3x heparin) or 10% sucrose (w/v). Three phases are observed in the low temperature regions at pH 3, 4, and 5-8. Phase boundaries corresponding to major heat-induced transitions are detected in the physiological temperature range. The highest thermal stabilities are observed near neutral pH (pH 6 and 7). Both heparin and sucrose appear to enhance the thermal stability of FGF-1, although their effects on the phase diagram are quite distinct. The greatest stabilization is observed at pH 8. Only heparin appears to protect FGF-1 from acid-induced unfolding to any extent.
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Affiliation(s)
- Haihong Fan
- Department of Pharmaceutical Chemistry, University of Kansas, 2030 Becker Dr., Lawrence, Kansas 66047, USA
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9
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Ghosh JG, Shenoy AK, Clark JI. Interactions between Important Regulatory Proteins and Human αB Crystallin. Biochemistry 2007; 46:6308-17. [PMID: 17487982 DOI: 10.1021/bi700149h] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Protein pin arrays assessed interactions between alphaB crystallin and 12 regulatory proteins, including EGF, FGF-2, IGF-1, NGF-beta, TGF-beta, VEGF, insulin, beta-catenin, caspase-3, caspase-8, Bcl-2, and Bcl-xL, which are important in cellular differentiation, proliferation, signaling, cytoskeletal assembly, and apoptosis. FGF-2, NGF-beta, VEGF, insulin, and beta-catenin had strong interactions with human alphaB crystallin peptides, and the alphaB crystallin interactive sequences for these proteins were identified. The seven remaining proteins (EGF, IGF-1, TGF-beta, caspase-3, caspase-8, BCl-2, and Bcl-xL) did not interact with alphaB crystallin. The alphaB crystallin sequences that interacted with FGF-2, NGF-beta, VEGF, insulin, and beta-catenin overlapped with sequences that selectively interact with partially unfolded proteins, suggesting a common function for alphaB crystallin in chaperone activity and the regulation of cell growth and differentiation. Chaperone assays conducted with full-length alphaB crystallin and synthetic alphaB crystallin peptides confirmed the ability of alphaB crystallin to protect against the aggregation of FGF-2 and VEGF, suggesting that alphaB crystallin protects these proteins against unfolding and aggregation under conditions of stress. This is the first report in which sequences involved in interactions with regulatory proteins, including FGF-2, NGF-beta, VEGF, insulin, and beta-catenin, were identified in a small heat shock protein.
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Affiliation(s)
- Joy G Ghosh
- Biomolecular Structure and Design, University of Washington, Seattle, Washington 98195-7420, USA
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10
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Derrick T, Grillo AO, Vitharana SN, Jones L, Rexroad J, Shah A, Perkins M, Spitznagel TM, Middaugh CR. Effect of Polyanions on the Structure and Stability of Repifermin™ (Keratinocyte Growth Factor-2). J Pharm Sci 2007; 96:761-76. [PMID: 17094125 DOI: 10.1002/jps.20797] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The interaction of several of the fibroblast growth factors (FGFs) with polyanions is thought to be of physiological significance and has been exploited to create more stable pharmaceutical formulations of FGF-1 and -2. The extent of such phenomena throughout the 23-member FGF family is, however, unknown. In these studies, we examine the effect of several polyanions on the structure and stability of keratinocyte growth factor 2 (KGF-2, FGF-10), a candidate for use as a wound-healing agent. Employing a variety of methods sensitive to the protein's structure including circular dichroism (CD), intrinsic fluorescence, derivative near-UV absorption spectroscopy, bis-ANS (4,4'-dianilino-1,1'-binaphthyl-5,5-disulfonic acid) fluorescence, differential scanning calorimetry (DSC), and dynamic light scattering (DLS), we find that a variety of polyanions (e.g., heparin, sucrose octasulfate (SOS), and inositol hexaphosphate (IHP)) stabilize KGF-2 by increasing the thermal-unfolding temperature by approximately 9-15 degrees C. Negatively charged liposomes produce a similar effect, arguing for relatively nonspecific interactions of polyanions with KGF-2. Unlike some other FGFs, no evidence for the presence of a molten globule state is found during thermal perturbation of this growth factor. The generality of this polyanion/protein interaction is discussed as well as its potential role in various cellular events such as protein folding and transport.
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11
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Fan H, Vitharana SN, Chen T, O'Keefe D, Middaugh CR. Effects of pH and Polyanions on the Thermal Stability of Fibroblast Growth Factor 20. Mol Pharm 2007; 4:232-40. [PMID: 17397238 DOI: 10.1021/mp060097h] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Fibroblast growth factor 20 (FGF20) is a member of the FGF family with potential for use in several different therapeutic categories. In this work, we provide the first structural characterization of FGF20 using a wide variety of approaches. Like other members of the FGF family, FGF20 appears to possess a beta-trefoil structure. The effect of pH on the conformation and thermal stability of FGF20 is evaluated using far-UV circular dichroism (CD), intrinsic and ANS fluorescence, and high-resolution derivative UV absorption spectroscopy. Empirical phase diagrams are constructed to describe the solution behavior of FGF20 over a wide pH and temperature range. The protein appears to be unstable at pH <5, with aggregation and precipitation observed during dialysis. A major heat-induced conformational change also causes aggregation and precipitation of FGF20 at elevated temperatures. The highest thermal stability is observed near neutral pH (Tm ~55 degrees C at pH 7). The effect of several high- and low-molecular mass polyanions on the thermal stability of FGF20 is also examined using CD, intrinsic fluorescence, and DSC analysis. Among these ligands, heparin exhibits the greatest stabilizing effect on FGF20, increasing the Tm by more than 10 degrees C.
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Affiliation(s)
- Haihong Fan
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66044, USA
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12
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Lucas LH, Ersoy BA, Kueltzo LA, Joshi SB, Brandau DT, Thyagarajapuram N, Peek LJ, Middaugh CR. Probing protein structure and dynamics by second-derivative ultraviolet absorption analysis of cation-{pi} interactions. Protein Sci 2006; 15:2228-43. [PMID: 16963649 PMCID: PMC2242397 DOI: 10.1110/ps.062133706] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
We describe an alternate approach for studying protein structure using the detection of ultraviolet (UV) absorbance peak shifts of aromatic amino acid side chains induced by the presence of salts. The method is based on the hypothesis that salt cations (Li+, Na+, and Cs+) of varying sizes can differentially diffuse through protein matrices and interact with benzyl, phenyl, and indole groups through cation-pi interactions. We have investigated the potential of this method to probe protein dynamics by measuring high resolution second-derivative UV spectra as a function of salt concentration for eight proteins of varying physical and chemical properties and the N-acetylated C-ethyl esterified amino acids to represent totally exposed side chains. We show that small shifts in the wavelength maxima for Phe, Tyr, and Trp in the presence of high salt concentrations can be reliably measured and that the magnitude and direction of the peak shifts are influenced by several factors, including protein size, charge, and the local environment and solvent accessibility of the aromatic groups. Evaluating the empirical UV spectral data in light of known protein structural information shows that probing cation-pi interactions in proteins reveals unique information about the influence of structure on aromatic side chain spectroscopic behavior.
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Affiliation(s)
- Laura H Lucas
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, Kansas 66047, USA
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13
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Voziyan PA, Johnston M, Chao A, Bomhoff G, Fisher MT. Designing a high throughput refolding array using a combination of the GroEL chaperonin and osmolytes. ACTA ACUST UNITED AC 2006; 6:183-8. [PMID: 16211517 DOI: 10.1007/s10969-005-2646-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2004] [Accepted: 02/16/2005] [Indexed: 11/25/2022]
Abstract
Although GroE chaperonins and osmolytes had been used separately as protein folding aids, combining these two methods provides a considerable advantage for folding proteins that cannot fold with either osmolytes or chaperonins alone. This technique rapidly identifies superior folding solution conditions for a broad array of proteins that are difficult or impossible to fold by other methods. While testing the broad applicability of this technique, we have discovered that osmolytes greatly simplify the chaperonin reaction by eliminating the requirement for the co-chaperonin GroES which is normally involved in encapsulating folding proteins within the GroEL-GroES cavity. Therefore, combinations of soluble or immobilized GroEL, osmolytes and ATP or even ADP are sufficient to refold the test proteins. The first step in the chaperonin/osmolyte process is to form a stable long-lived chaperonin-substrate protein complex in the absence of nucleotide. In the second step, different osmolyte solutions are added along with nucleotides, thus forming a 'folding array' to identify superior folding conditions. The stable chaperonin-substrate protein complex can be concentrated or immobilized prior to osmolyte addition. This procedure prevents-off pathway aggregation during folding/refolding reactions and more importantly allows one to refold proteins at concentrations (approximately mg/ml) that are substantially higher than the critical aggregation concentration for given protein. This technique can be used for successful refolding of proteins from purified inclusion bodies. Recently, other investigators have used our chaperonin/osmolyte method to demonstrate that a mutant protein that misfolds in human disease can be rescued by GroEL/osmolyte system. Soluble or immobilized GroEL can be easily removed from the released folded protein using simple separation techniques. The method allows for isolation of folded monomeric or oligomeric proteins in quantities sufficient for X-ray crystallography or NMR structural determinations.
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Affiliation(s)
- Paul A Voziyan
- Department of Medicine/Nephrology, Vanderbilt University Medical Center, Nashville, TN 37232-2372, USA
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14
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Fisher MT. Molecular roles of chaperones in assisted folding and assembly of proteins. GENETIC ENGINEERING 2006; 27:191-229. [PMID: 16382878 DOI: 10.1007/0-387-25856-6_11] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/05/2023]
Affiliation(s)
- Mark T Fisher
- Department of Biochemistry and Molecular Biology, University of Kansas Medical Center, Kansas City, Kansas 66160, USA
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15
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Abstract
The behavior of the proteome reflects spatial and temporal organization both within and without cells. We propose that various macromolecular entities possessing polyanionic character such as proteoglycans, lipid bilayer surfaces, microtubules, microfilaments, and polynucleotides may provide a functional network that mediates a variety of cellular phenomena. The interaction of proteins with this array of polyanions is characterized by a lower degree of specificity than seen with most commonly recognized macromolecular interactions. In this commentary, potential roles for this polyanion network in diverse functions such as protein/protein interactions, protein folding and stabilization, macromolecular transport, and various disease processes are all considered, as well as the use of polyanions as therapeutic agents. The role of small polyanions in the regulation of protein/polyanion interactions is also postulated. We provide preliminary experimental analysis of the extent to which proteins interact with polyanions inside cells using a combination of two-dimensional chromatographic and electrophoretic methods and antibody arrays. We conclude that many hundreds to thousands of such interactions are present in cells and argue that future understanding of the proteome will require that the "polyanion world" be taken into account.
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Affiliation(s)
- LaToya S Jones
- Department of Pharmaceutical Chemistry, University of Kansas, Lawrence, KS 66047-3729, USA
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16
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Gu Z, Zhu X, Ni S, Su Z, Zhou HM. Conformational changes of lysozyme refolding intermediates and implications for aggregation and renaturation. Int J Biochem Cell Biol 2004; 36:795-805. [PMID: 15006632 DOI: 10.1016/j.biocel.2003.08.015] [Citation(s) in RCA: 73] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2003] [Revised: 08/06/2003] [Accepted: 08/12/2003] [Indexed: 11/26/2022]
Abstract
It is believed that denatured-reduced lysozyme rapidly forms aggregates during refolding process, which is often worked around by operating at low protein concentrations or in the presence of aggregation inhibitors. However, we found that low concentration buffer alone could efficiently suppress aggregation. Based on this finding, stable equilibrium intermediate states of denatured-reduced lysozyme containing eight free SH groups were obtained in the absence of redox reagents in buffer of low concentrations alone at neutral or mildly alkaline pH. Transition in the secondary structure of the intermediate from native-like to beta-sheet was observed by circular dichroism (CD) as conditions were varied. Dynamic light scattering and ANS-binding studies showed that the self-association accompanied the conformational change and the structure rich in beta-sheet was the intermediate state for aggregation, which could form either amyloid protofibril or amorphous aggregates under different conditions as detected by Electron Microscopy. Combining the results obtained from activity analysis, RP-HPLC and CD, we show that the activity recovery was closely related to the conformation of the refolding intermediate, and buffer of very low concentration (e.g. 10mM) alone could efficiently promote correct refolding by maintaining the native-like secondary structure of the intermediate state. This study reveals reasons for lysozyme aggregation and puts new insights into protein and inclusion body refolding.
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Affiliation(s)
- Zhenyu Gu
- Department of Biological Science and Biotechnology, Tsinghua University, Beijing 100084, China
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17
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Kueltzo LA, Middaugh CR. Nonclassical transport proteins and peptides: an alternative to classical macromolecule delivery systems. J Pharm Sci 2003; 92:1754-72. [PMID: 12949995 DOI: 10.1002/jps.10448] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
The number of peptides and proteins known to exhibit nonclassical transport activity has increased significantly in recent years. In most cases, these entities have been studied in relation to their ability to deliver high molecular weight compounds, including proteins and DNA, for the ultimate purpose of developing new drug delivery strategies. In this review, an overview of the various types of vectors is presented. The in vitro and in vivo delivery successes of this technology, as well as preliminary therapeutic efforts, are described. Although a comprehensive mechanism of nonclassical transport has not yet been clearly established, we propose a straightforward model based on the cationic nature of the vectors and the need for lack of highly organized structure. In this hypothesis we suggest that the movement of polycations is mediated by a network of extra- and intracellular polyanions while transport across the bilayer is facilitated by cation-pi interactions between the vectors' basic groups and aromatic amino acid side chains in the bilayer spanning helices of membrane proteins.
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Affiliation(s)
- Lisa A Kueltzo
- Department of Pharmaceutical Chemistry, University of Kansas, 2095 Constant Ave., Lawrence, Kansas 66047, USA
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