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Kerr R, Agrawal S, Maity S, Koppolu B, Jayanthi S, Suresh Kumar G, Gundampati RK, McNabb DS, Zaharoff DA, Kumar TKS. Design of a thrombin resistant human acidic fibroblast growth factor (hFGF1) variant that exhibits enhanced cell proliferation activity. Biochem Biophys Res Commun 2019; 518:191-196. [PMID: 31420170 DOI: 10.1016/j.bbrc.2019.08.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2019] [Accepted: 08/06/2019] [Indexed: 12/22/2022]
Abstract
Acidic fibroblast growth factors (FGF1s) are heparin binding proteins that regulate a wide array of key cellular processes and are also candidates for promising biomedical applications. FGF1-based therapeutic applications are currently limited due to their inherent thermal instability and susceptibility to proteases. Using a wide range of biophysical and biochemical techniques, we demonstrate that reversal of charge on a well-conserved positively charged amino acid, R136, in the heparin binding pocket drastically increases the resistance to proteases, thermal stability, and cell proliferation activity of the human acidic fibroblast growth factor (hFGF1). Two-dimensional NMR data suggest that the single point mutations at position-136 (R136G, R136L, R136Q, R136K, and R136E) did not perturb the backbone folding of hFGF1. Results of the differential scanning calorimetry experiments show that of all the designed R136 mutations only the charge reversal mutation, R136E, significantly increases (ΔTm = 7 °C) the thermal stability of the protein. Limited trypsin and thrombin digestion results reveal that the R136E mutation drastically increases the resistance of hFGF1 to the action of the serine proteases. Isothermal titration calorimetry data show that the R136E mutation markedly decreases the heparin binding affinity of hFGF1. Interestingly, despite lower heparin binding affinity, the cell proliferation activity of the R136E variant is more than double of that exhibited by either the wild type or the other R136 variants. The R136E variant due to its increased thermal stability, resistance to proteases, and enhanced cell proliferation activity are expected to provide valuable clues for the development of hFGF1- based therapeutics for the management of chronic diabetic wounds.
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Affiliation(s)
- Rebecca Kerr
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Shilpi Agrawal
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Sanhita Maity
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Bhanuprasanth Koppolu
- Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill & North Carolina State University, Raleigh, NC, 27695, USA
| | - Srinivas Jayanthi
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Gayatri Suresh Kumar
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - Ravi Kumar Gundampati
- Department of Chemistry and Biochemistry, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - David S McNabb
- Department of Biological Sciences, University of Arkansas, University of Arkansas, Fayetteville, AR, 72701, USA
| | - David A Zaharoff
- Joint Department of Biomedical Engineering, University of North Carolina-Chapel Hill & North Carolina State University, Raleigh, NC, 27695, USA
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Ghosh G, Mandal DK. Novel unfolding sequence of banana lectin: Folded, unfolded and natively unfolded-like monomeric states in guanidine hydrochloride. Biochimie 2013; 99:138-45. [PMID: 24316282 DOI: 10.1016/j.biochi.2013.11.022] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Accepted: 11/23/2013] [Indexed: 11/16/2022]
Abstract
The sequence of unfolding events of dimeric banana lectin (Banlec), as induced by guanidine hydrochloride (GdnHCl), has been investigated by size-exclusion HPLC, fluorescence, far-UV CD, low temperature phosphorescence and selective chemical modification. 8-Anilino-1-naphthalenesulfonate (ANS) binding indicates a structured unfolding intermediate which has been characterized as dissociated monomer by size-exclusion chromatography. Interestingly, the unfolding elution pattern reveals two distinct unfolded states. One is a usual random coil. The other represents a novel species having elution behavior and structural compactness (Stokes radius) similar to dissociated monomer but showing no regular secondary structure as determined by far-UV CD, thus resembling a natively unfolded state. N-Bromosuccinimide (NBS) oxidation shows that single tryptophan residue remains unmodified in dissociated monomer intermediate while the same is oxidized in natively unfolded-like species. Such difference in tryptophan environment in these species is supported by acrylamide quenching studies, and phosphorescence results at 77 K which show a blue-shift of (0,0) band from 414.8 nm to 409.2 nm. The present results reveal subtlety of structural characteristics of unfolded states of Banlec in GdnHCl, which provide important insight in protein unfolding reaction.
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Affiliation(s)
- Goutam Ghosh
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India
| | - Dipak K Mandal
- Department of Chemistry, Presidency University, 86/1 College Street, Kolkata 700 073, India.
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Thurman RD, Kathir KM, Rajalingam D, Kumar TKS. Molecular basis for the Kallmann syndrome-linked fibroblast growth factor receptor mutation. Biochem Biophys Res Commun 2012; 425:673-8. [PMID: 22842457 DOI: 10.1016/j.bbrc.2012.07.104] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2012] [Accepted: 07/19/2012] [Indexed: 12/21/2022]
Abstract
Kallmann syndrome (KS) is a developmental disease that expresses in patients as hypogonadotropic hypogonadism and anosmia. KS is commonly associated with mutations in the extracellular D2 domain of the fibroblast growth factor receptor (FGFR). In this study, for the first time, the molecular basis for the FGFR associated KS mutation (A168S) is elucidated using a variety of biophysical experiments, including multidimensional NMR spectroscopy. Secondary and tertiary structural analysis using far UV circular dichroism, fluorescence and limited trypsin digestion assays suggest that the KS mutation induces subtle tertiary structure change in the D2 domain of FGFR. Results of isothermal titration calorimetry experiments show the KS mutation causes a 10-fold decrease in heparin binding affinity and also a complete loss in ligand (FGF-1) binding. (1)H-(15)N chemical perturbation data suggest that complete loss in the ligand (FGF) binding affinity is triggered by a subtle conformational change that disrupts crucial structural interactions in both the heparin and the FGF binding sites in the D2 domain of FGFR. The novel findings reported in this study are expected to provide valuable clues toward a complete understanding of the other genetic diseases linked to mutations in the FGFR.
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Affiliation(s)
- Ryan D Thurman
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, AR 72701, USA
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Vaz AF, Costa RM, Coelho LC, Oliva ML, Santana LA, Melo AM, Correia MT. Gamma irradiation as an alternative treatment to abolish allergenicity of lectins in food. Food Chem 2011. [DOI: 10.1016/j.foodchem.2010.07.098] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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Khrapunov S, Cheng H, Hegde S, Blanchard J, Brenowitz M. Solution structure and refolding of the Mycobacterium tuberculosis pentapeptide repeat protein MfpA. J Biol Chem 2008; 283:36290-9. [PMID: 18977756 PMCID: PMC2606005 DOI: 10.1074/jbc.m804702200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2008] [Revised: 10/20/2008] [Indexed: 11/06/2022] Open
Abstract
The pentapeptide repeat is a recently discovered protein fold. Mycobacterium tuberculosis MfpA is a founding member of the pentapeptide repeat protein (PRP) family that confers resistance to the antibiotic fluoroquinolone by binding to DNA gyrase and inhibiting its activity. The size, shape, and surface potential of MfpA mimics duplex DNA. As an initial step in a comprehensive biophysical analysis of the role of PRPs in the regulation of cellular topoisomerase activity and conferring antibiotic resistance, we have explored the solution structure and refolding of MfpA by fluorescence spectroscopy, CD, and analytical centrifugation. A unique CD spectrum for the pentapeptide repeat fold is described. This spectrum reveals a native structure whose beta-strands and turns within the right-handed quadrilateral beta-helix that define the PRP fold differ from canonical secondary structure types. MfpA refolded from urea or guanidium by dialysis or dilution forms stable aggregates of monomers whose secondary and tertiary structure are not native. In contrast, MfpA refolded using a novel "time-dependent renaturation" protocol yields protein with native secondary, tertiary, and quaternary structure. The generality of "time-dependent renaturation" to other proteins and denaturation methods is discussed.
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Affiliation(s)
- Sergei Khrapunov
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Sivaraja V, Kumar TKS, Rajalingam D, Graziani I, Prudovsky I, Yu C. Copper binding affinity of S100A13, a key component of the FGF-1 nonclassical copper-dependent release complex. Biophys J 2006; 91:1832-43. [PMID: 16766622 PMCID: PMC1544301 DOI: 10.1529/biophysj.105.079988] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
S100A13 is a member of the S100 protein family that is involved in the copper-dependent nonclassical secretion of signal peptideless proteins fibroblast growth factor 1 and interleukin 1 lpha. In this study, we investigate the effects of interplay of Cu2+ and Ca2+ on the structure of S100A13 using a variety of biophysical techniques, including multi-dimensional NMR spectroscopy. Results of the isothermal titration calorimetry experiments show that S100A13 can bind independently to both Ca2+ and Cu2+ with almost equal affinity (Kd in the micromolar range). Terbium binding and isothermal titration calorimetry data reveal that two atoms of Cu2+/Ca2+ bind per subunit of S100A13. Results of the thermal denaturation experiments monitored by far-ultraviolet circular dichroism, limited trypsin digestion, and hydrogen-deuterium exchange (using 1H-15N heteronuclear single quantum coherence spectra) reveal that Ca2+ and Cu2+ have opposite effects on the stability of S100A13. Binding of Ca2+ stabilizes the protein, but the stability of the protein is observed to decrease upon binding to Cu2+. 1H-15N chemical shift perturbation experiments indicate that S100A13 can bind simultaneously to both Ca2+ and Cu2+ and the binding of the metal ions is not mutually exclusive. The results of this study suggest that the Cu2+-binding affinity of S100A13 is important for the formation of the FGF-1 homodimer and the subsequent secretion of the signal peptideless growth factor through the nonclassical release pathway.
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Affiliation(s)
- Vaithiyalingam Sivaraja
- Department of Chemistry and Biochemistry, University of Arkansas, Fayetteville, Arkansas 72701, USA
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Kliemannel M, Weininger U, Balbach J, Schwarz E, Rudolph R. Examination of the slow unfolding of pro-nerve growth factor argues against a loop threading mechanism for nerve growth factor. Biochemistry 2006; 45:3517-24. [PMID: 16533032 DOI: 10.1021/bi051896t] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Nerve growth factor (NGF), a member of the neurotrophin family, is an all-beta-sheet protein with a characteristic structure motif, the cystine knot. Unfolding of NGF in 6 M GdnHCl has been described previously to involve an initial partial loss of structure and a subsequent very slow conversion to a second, completely unfolded state. This latter conversion was postulated to represent a back-threading of the disulfide bond that passes through the cystine knot (loop threading hypothesis). Here, this hypothesis was questioned with the pro form of the protein (proNGF). In proNGF, the mature part is preceded by the 103-amino acid pro-peptide. Consequently, loop threading of the N-terminally extended protein should be significantly delayed. However, unfolding kinetics of proNGF monitored by RP-HPLC, intrinsic fluorescence, and NMR spectroscopy were comparable to those of mature NGF. Time-resolved (1)H-(15)N HSQC spectra revealed a slow time-dependent loss of residual structure of which the kinetics correlated well with the transition observed by RP-HPLC. Refolding from the completely unfolded state led to a partial recovery of natively folded proNGF. In summary, the sequential unfolding of proNGF only marginally differed from that of mature NGF. Therefore, it is very unlikely that a loop threading mechanism is the cause of the slow unfolding step.
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Affiliation(s)
- Marco Kliemannel
- Institut für Biotechnologie der Martin-Luther-Universität Halle-Wittenberg, Kurt-Mothes-Strasse 3, 06120 Halle, Germany
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