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Leigh T, Fernandez-Trillo P. Helical polymers for biological and medical applications. Nat Rev Chem 2020; 4:291-310. [PMID: 37127955 DOI: 10.1038/s41570-020-0180-5] [Citation(s) in RCA: 74] [Impact Index Per Article: 18.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/24/2020] [Indexed: 12/14/2022]
Abstract
Helices are the most prevalent secondary structure in biomolecules and play vital roles in their activity. Chemists have been fascinated with mimicking this molecular conformation with synthetic materials. Research has now been devoted to the synthesis and characterization of helical materials, and to understand the design principles behind this molecular architecture. In parallel, work has been done to develop synthetic polymers for biological and medical applications. We now have access to materials with controlled size, molecular conformation, multivalency or functionality. As a result, synthetic polymers are being investigated in areas such as drug and gene delivery, tissue engineering, imaging and sensing, or as polymer therapeutics. Here, we provide a critical view of where these two fields, helical polymers and polymers for biological and medical applications, overlap. We have selected relevant polymer families and examples to illustrate the range of applications that can be targeted and the impact of the helical conformation on the performance. For each family of polymers, we briefly describe how they can be prepared, what helical conformations are observed and what parameters control helicity. We close this Review with an outlook of the challenges ahead, including the characterization of helicity through the process and the identification of biocompatibility.
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Braam WG, Harmsen BJ, Walters JA, van Os GA. Isolation and characterization of some fragments obtained after peptic digestion of bovine serum albumin. INTERNATIONAL JOURNAL OF PROTEIN RESEARCH 2009; 3:277-83. [PMID: 4944749 DOI: 10.1111/j.1399-3011.1971.tb01721.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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4
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Barksdale AD, Rosenberg A. Acquisition and interpretation of hydrogen exchange data from peptides, polymers, and proteins. METHODS OF BIOCHEMICAL ANALYSIS 2006; 28:1-113. [PMID: 7048016 DOI: 10.1002/9780470110485.ch1] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Maget-Dana R, Lelièvre D, Brack A. Surface active properties of amphiphilic sequential isopeptides: Comparison between alpha-helical and beta-sheet conformations. Biopolymers 1999; 49:415-423. [PMID: 11180048 DOI: 10.1002/(sici)1097-0282(19990415)49:5<415::aid-bip7>3.0.co;2-j] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Poly(Leu-Lys-Lys-Leu) and poly(Leu-Lys) are sequential amphiphilic peptide isomers that adopt respectively an alpha-helical conformation and a beta-sheet structure in saline solutions and at the air/water interface. The surface active properties of LKKL and LK sequential isopeptides containing 16, 20, and n residues have been compared in order to evaluate the contributions of the alpha-helical and beta-sheet conformations. Both have a natural tendency to spread at the surface of a saline solution and the values of the equilibrium spreading pressure pi(e) lie in the same range. When dissolved in a saline solution, alpha-helical peptides diffuse faster and adsorb faster at the interface than the beta-sheet isomers. From the compression isotherms of LKKL and LK peptide monolayers it is possible to extract parameters that characterize the behavior of alpha-helical and beta-sheet conformations: beta-sheet peptide monolayers are more stable and less compressible than the monolayers formed with the alpha-helical isomers. The LK peptides differ also by their high degree of self-association at the air/water interface. Copyright 1999 John Wiley & Sons, Inc.
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Affiliation(s)
- Régine Maget-Dana
- Centre de Biophysique Moléculaire, CNRS, 45071 Orléans Cedex 2, France
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D'Alagni M, D'Archivio AA, Giglio E. On the interaction of polypeptides with bile salts or bilirubin-IX alpha. Biopolymers 1993; 33:1553-65. [PMID: 8218923 DOI: 10.1002/bip.360331006] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
Aqueous solutions formed by polypeptides, simple models of proteins, and bile salts (sodium cholate and deoxycholate, NaC and NaDC, respectively) or bilirubin-IX alpha (BR) have been studied by CD measurements. They could mimic more complicated biliary systems, thus supplying a possible interpretation of the behavior of some amino acid residues in the biliary proteins. The aggregation of NaDC and NaC in water can be monitored by CD measurements. Bile salts, in submicellar and micellar form, stabilize poly(L-Lys) (PLL) in alpha-helical conformation. The alpha-helix content increases with increasing bile salt concentration and ionic strength. NaDC seems to be a slightly better stabilizing agent of the alpha-helix conformation than NaC. Models characterized by hydrogen bonds between bile salts and PLL are proposed, also resorting to previous data available on the systems formed by NaDC and poly(L-Leu-L-Leu-L-Lys) (PLLL) or poly(L-Leu-L-Leu-L-Asp) (PLLA). Binding of BR to PLL, poly(D-Lys), poly(L-Glu), PLLL, and PLLA in water has been investigated by CD spectra in order to clarify the nature of the association complexes and the mechanism of the BR enantioselective complexation. Potential energy calculations provide binding models capable of explaining the enantioselective ability of the PLL and PLLL alpha-helices toward the left- and right-handed enantiomer of BR, respectively. BR is bound to -NH2 groups of PLL and PLLL lying on a right- and left-handed spiral, respectively. These results, together with those formerly obtained for some bile salts-BR systems, indicate that the selectivity originates from a binding that involves large regions of the BR molecule and gives rise, very probably, to moderate conformational changes from the "ridge tile" structure observed in the crystals. In some cases van der Waals forces can play a crucial role in the chiral recognition of bilirubin. Moreover, possible interaction models of BR with human serum albumin are proposed on the basis of a recent x-ray crystal structure of the protein.
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Affiliation(s)
- M D'Alagni
- Dipartimento di Chimica, Università di Roma La Sapienza, Italy
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Collawn JF, Paterson Y. Stabilization of helical structure in two 17-residue amphipathic analogues of the C-terminal peptide of cytochrome C. Biopolymers 1990; 29:1289-96. [PMID: 2164428 DOI: 10.1002/bip.360290817] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
The conformations of two 17-residue peptide analogues derived from the C-terminal sequence of pigeon cytochrome c (native sequence = KAERADLIAYLKQATAK) were examined in aqueous and lipid environments by CD spectroscopy. The two analogues, KKLLKKLIAYLKQATAK (K peptide) and EELLEELIAYLKQATAK (E peptide), were made amphipathic with respect to helical segregation by substituting a 6-residue sequence at the N-terminus of the native peptide. Their structures were compared to the native peptide under aqueous conditions of varying pH and temperature, and in the presence of liposomes composed of phosphatidylcholine and phosphatidylserine in the ratio of 9:1. The results indicated that the native peptide remains unstructured under all the conditions examined even though this region of the native molecule is surface exposed and helical. The E peptide, however, was helical under aqueous conditions at 25 degrees C from pH 2-10 with a maximum helicity at pH 4 (54% helix from analysis of CD data). The ellipticity of the E peptide at pH 4 and 8 was concentration dependent, indicating an aggregation phenomenon. In studies in which the CD spectrum was measured at different temperatures, the E peptide became more helical at lower temperatures at pH 4 but not at pH 8. Upon interaction with a lipid membrane in the form of liposomes, there appeared to be a slight destabilization in the structure of the E peptide. The K peptide in an aqueous environment behaved like the native peptide in that it was structureless at all pHs and temperatures examined. In the presence of liposomes, however, this peptide had a high helical content (75% helix from analysis of CD data). These findings suggest that while stabilization of the helix dipole with negative charges at the N-terminus are important in inducing helical conformation in the E peptide, hydrophobic interactions created during aggregation appear to provide the principal stabilizing force. The results with the K peptide demonstrate that the positive N-terminal sequence of this peptide is able to interact with the negatively charged head groups in the phospholipid membrane in such a fashion as to stabilize a helical structure that is not apparent in an aqueous environment alone.
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Affiliation(s)
- J F Collawn
- Department of Cancer Biology, Salk Institute, La Jolla, California 92037
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Venyaminov SYu, Kalnin NN. Quantitative IR spectrophotometry of peptide compounds in water (H2O) solutions. II. Amide absorption bands of polypeptides and fibrous proteins in alpha-, beta-, and random coil conformations. Biopolymers 1990; 30:1259-71. [PMID: 1707690 DOI: 10.1002/bip.360301310] [Citation(s) in RCA: 204] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Infrared spectra of poly(D,L-alanine), poly(L-glutamic acid), poly(L-lysine), silk fibroin, and tropomyosin have been registered for various conformations of the polypeptide chain. Assuming additivity of the main- and side-chain absorption, spectral parameters of amide I and II absorption bands corresponding to alpha-, beta-, and random coil conformations have been derived. The amide I band parameters for H2O and D2O have been compared.
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Affiliation(s)
- Venyaminov SYu
- Institute of Protein Research, Academy of Sciences of the USSR, Puschino, Moscow Region
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Fujii S, Tatsumoto N, Yamaoka K. Polarographic study of poly(α-D-glutamic acid) in acid solutions. ACTA ACUST UNITED AC 1986. [DOI: 10.1016/0302-4598(86)85002-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
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Chapter 4 Absorption, circular dichroism and optical rotatory dispersion of polypeptides, proteins, prosthetic groups and biomembranes. ACTA ACUST UNITED AC 1985. [DOI: 10.1016/s0167-7306(08)60563-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register]
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Era S, Ashida H, Nagaoka S, Inouye H, Sogami M. CD-resolved secondary structure of bovine plasma albumin in acid-induced isomerization. INTERNATIONAL JOURNAL OF PEPTIDE AND PROTEIN RESEARCH 1983; 22:333-40. [PMID: 6629647 DOI: 10.1111/j.1399-3011.1983.tb02099.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Bovine plasma albumin (BPA) showed the acid-induced two-step transition, the N-F transition and acid-expansion. Changes in fractions of alpha-helix (f alpha), beta-form (f beta) and unordered form (fR) in the acid-induced isomerization of BPA were studied using the method of Chen et al. (1972) with two constraints: sigma fi = 1, 0 less than or equal to fi less than or equal to 1. pH-profiles of f alpha and fR showed the two-step change, one corresponding to the N-F transition and the other to the acid-expansion in 0.10 M KCl and in 0.02 M NaClO4. pH-profile of f beta showed one-step change, correlating to the later part (lower pH side) of the N-F transition. The N-F transition might thus involve the helix leads to beta and helix leads to coil transitions.
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Masujima T, Yamaoka K, Hori JI. Conformational Changes of the Poly(α-L-glutamic acid)–Cu(II) Macromolecular Complexes in the pH Range 4–7. A Comparative Study by Means of Viscosity and Circular Dichroism. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1983. [DOI: 10.1246/bcsj.56.1030] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Masujima T. Conformational Changes of the Poly(α-L-glutamic acid)–Cu(II) Macromolecular Complexes in the pH Range of 4–7. A Light Scattering Study with Emphasis on Aggregation and Helix-coil Transitions. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1983. [DOI: 10.1246/bcsj.56.838] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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14
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Pefferkorn E, Schmitt A, Varoqui R. Helix-coil transition of poly(?,L-glutamic acid) at an interface: Correlation with static and dynamic membrane properties. Biopolymers 1982. [DOI: 10.1002/bip.360210713] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Yamaoka K, Shimadzu M. THE J BAND OF THE MALACHITE GREEN-POLY(α-L-GLUTAMIC ACID) COMPLEX: THE CONDITIONS FOR ITS APPEARANCE IN AQUEOUS SOLUTIONS. CHEM LETT 1982. [DOI: 10.1246/cl.1982.583] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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16
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Long MM, Urry DW. Absorption and circular dichroism spectroscopies. MOLECULAR BIOLOGY, BIOCHEMISTRY, AND BIOPHYSICS 1981; 31:143-71. [PMID: 6164912 DOI: 10.1007/978-3-642-81537-9_3] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
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17
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Spectroscopic and equilibrium dialysis studies of poly(?-L-glutamic acid)-Cu(II) complexes in the pH range 4-7. Biopolymers 1980. [DOI: 10.1002/bip.1980.360190304] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
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18
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Yamaoka K, Masujima T. The Visible-UV Absorption and Circular Dichroism Studies of Poly(α-L-glutamic acid)–Copper(II) Complexes with Emphasis on the Extrinsic Cotton Effect. BULLETIN OF THE CHEMICAL SOCIETY OF JAPAN 1979. [DOI: 10.1246/bcsj.52.1286] [Citation(s) in RCA: 31] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
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Howell RM, Rezvan H, Scopes PM. Conformational transitions of thromboplastin apoprotein from pig brain. FEBS Lett 1979; 97:23-6. [PMID: 761618 DOI: 10.1016/0014-5793(79)80043-5] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
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20
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Lee N, Cheng E, Inouye M. Optical properties of an outer membrane lipoprotein from Escherichia coli. BIOCHIMICA ET BIOPHYSICA ACTA 1977; 465:650-6. [PMID: 319831 DOI: 10.1016/0005-2736(77)90280-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
The infrared spectrum of a structural lipoprotein from the Escherichia coli outer membrane indicated the lipoprotein had an alpha-helical conformation but no sign for the existence of beta-structures. From circular dichroism spectra of the lipoprotein, the alpha-helical content of the protein was found to be as high as 88% in 0.01-0.03% sodium dodecyl sulfate in the presence of 10(-5) M Mg2+ at pH 7.1 and 23 degrees C. When sodium dodecyl sulfate concentration increased higher than 0.1%, the alpha-helical content of the lipoprotein decreased to about 57%. Divalent cations, such as Mg2+ and Mn2+, were found to increase the helical content of the lipoprotein. The high alpha-helical content of the lipoprotein was observed in a wide range of temperatures (23 to 55 degrees C). The significance of the high alpha-helical content of the lipoprotein is discussed in light of the three-dimensional molecular models of the lipoprotein proposed previously.
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Zimmerman SS, Clark JC, Mandelkern L. The precipitation of poly-L-glutamic acid. II. beta-Precipitation. Biopolymers 1975; 14:585-96. [PMID: 1174680 DOI: 10.1002/bip.1975.360140312] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
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24
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Zimmerman SS, Mandelkern L. The precipitation of poly-L-glutamic acid. I. Alpha-precipitation. Biopolymers 1975; 14:567-84. [PMID: 240460 DOI: 10.1002/bip.1975.360140311] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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25
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Sawyer WH. Self-association, conformation and binding equilibria of concanavalin A. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1975; 55:71-95. [PMID: 239535 DOI: 10.1007/978-1-4684-0949-9_5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
The discovery of distinct intact and fragmented forms of Con A, together with the observation that Con A self-associates near neutrality raises questions that may be important when interpreting experiments concerned with the biological actions of the protein. Do intact and fragmented units have the same affinity for carbohydrate? Do intact and fragmented units differ in conformation? Are all dimeric units of a homologous type or do hybrid dimers consisting of one intact and one fragmented unit also exist? Can all dimeric types self-associate to the tetramer form? Do dimer and tetramer species differ in their affinity for carbohydrate? These questions have been made amenable to investigation by the development of a method which separates intact and fragmented species under conditions which do not cause time-dependent or irreversible changes in protein conformation. It is found that intact dimeric units preferentially associate to the tetramer form. Under appropriate conditions of pH and ionic strength, dimer and tetramer species, and therefore fragmented and intact forms, can be separated by chromatography on Bio Gel P-100. Hybrid dimers are not present in appreciable amounts. Both types of homologous dimers (intact and fragmented) have similar affinity for carbohydrate, but dimer and tetramer species show significant differences. The results of near UV circular dichroism studies indicate that fragmented units possess slightly different conformation than intact units. An ionization-linked conformational transition in Con A does not appear to be linked directly with the self-association of the protein between pH 5 and 7. Ligand-induced changes in the conformation of Con A are now being examined in detail. Pflumm et al. (1971) have shown that occupation of the sugar binding site of Con A results in a perturbation of conformation as revealed by near UV circular dichroism measurements. The perturbation is relatively small and does not result in more than 1-2% increase in the rotational relaxation time (Shinitzky et al., 1973). On the other hand, removal of metal ions causes a hydrodynamic change sufficient to increase the frictional coefficient and to decrease the sedimentation coefficient (S20, w) from 3.98 S to 3.78 S. Differences between the native and the apoprotein conformation are now being examined using fluorescence polarization and the hydrophobic fluorescent probe 1-anilinonaphthalene-8-sulfonate.
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Welch WH, Fasman GD. Hydrogen-tritium exchange in polypeptides. Models of alpha-helical and beta conformations. Biochemistry 1974; 13:2455-66. [PMID: 4208842 DOI: 10.1021/bi00709a001] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Irons L, Evans MT, Jones M, Miller PJ. The effect of succinylation and acylation on the physicochemical properties of alpha-s1-casein B. BIOCHIMICA ET BIOPHYSICA ACTA 1973; 328:433-47. [PMID: 4798150 DOI: 10.1016/0005-2795(73)90278-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Matsumoto M, Watanabe H, Yoshioka K. Electric and hydrodynamic properties of polypeptides in solution. IV. A new conformational change of poly(L-glutamic acid) in dimethylsulfoxide-methanol mixtures. Biopolymers 1973; 12:1729-39. [PMID: 4733705 DOI: 10.1002/bip.1973.360120803] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
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Reversible Denaturation of Human Serum Albumin by pH, Temperature, and Guanidine Hydrochloride Followed by Optical Rotation. J Biol Chem 1973. [DOI: 10.1016/s0021-9258(19)44056-8] [Citation(s) in RCA: 159] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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Urry DW. CONFORMATION OF PROTEIN IN BIOLOGICAL MEMBRANES AND A MODEL TRANSMEMBRANE CHANNEL*. Ann N Y Acad Sci 1972; 195:108-125. [DOI: 10.1111/j.1749-6632.1972.tb54789.x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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31
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Warashina A, Ikegami A. Thermal and charge-induced coil to -helix transition of poly-L-glutamic acid and random L-glutamic acid-L-alanine copolymers. Biopolymers 1972; 11:529-47. [PMID: 5016115 DOI: 10.1002/bip.1972.360110302] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Urry DW. Protein conformation in biomembranes: optical rotation and absorption of membrane suspensions. BIOCHIMICA ET BIOPHYSICA ACTA 1972; 265:115-68. [PMID: 4552304 DOI: 10.1016/0304-4157(72)90021-4] [Citation(s) in RCA: 180] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Evans MT, Irons L, Petty JH. Physicochemical properties of some acyl derivatives of -casein. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 243:259-72. [PMID: 5122660 DOI: 10.1016/0005-2795(71)90083-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Budzynski AZ, Means GE. Inhibition of polymerization of tobacco mosaic virus protein by modification of carboxyl groups. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 236:767-76. [PMID: 5559971 DOI: 10.1016/0005-2795(71)90261-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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36
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Chou PY, Scheraga HA. Calorimetric measurement of enthalpy change in the isothermal helix--coil transition of poly-L-lysine in aqueous solution. Biopolymers 1971; 10:657-80. [PMID: 5552138 DOI: 10.1002/bip.360100406] [Citation(s) in RCA: 92] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Budzynski AZ. Difference in conformation of fibrinogen degradation products as revealed by hydrogen exchange and spectropolarimetry. BIOCHIMICA ET BIOPHYSICA ACTA 1971; 229:663-71. [PMID: 4252126 DOI: 10.1016/0005-2795(71)90282-0] [Citation(s) in RCA: 33] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
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Cassim JY, Yang JT. Critical comparison of the experimental optical activity of helical polypeptides and the predictions of the molecular exciton model. Biopolymers 1970; 9:1475-502. [PMID: 5489315 DOI: 10.1002/bip.1970.360091209] [Citation(s) in RCA: 61] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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The Effect of Aliphatic Alcohols on the Helix-Coil Transition of Poly-l-ornithine and Poly-l-glutamic Acid. J Biol Chem 1970. [DOI: 10.1016/s0021-9258(18)63000-5] [Citation(s) in RCA: 86] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
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Urry DW, Hinners TA, Masotti L. Calculation of distorted circular dichroism curves for poly-L-glutamic acid suspensions. Arch Biochem Biophys 1970; 137:214-21. [PMID: 5435058 DOI: 10.1016/0003-9861(70)90428-5] [Citation(s) in RCA: 65] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Wilson WD, Foster JF. Alterations in proteins and polyamino acids caused by ultraviolet irradiation in a spectropolarimeter. Biochem Biophys Res Commun 1970; 38:552-8. [PMID: 5462698 DOI: 10.1016/0006-291x(70)90616-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Herskovits TT, Menéndez CJ. The optical rotatory dispersion and circular dichroism of ribonuclease and its subtilisin modified derivatives. Arch Biochem Biophys 1969; 135:452-4. [PMID: 5391474 DOI: 10.1016/0003-9861(69)90562-1] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
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Ciferri A, Puett D, Rajagh L, Hermans J. Potentiometric titrations and the helix-coil transition of poly(L-glutamic acid) and poly-L-lysine in aqueous salt solutions. Biopolymers 1968; 6:119-36. [PMID: 5663413 DOI: 10.1002/bip.1968.360060803] [Citation(s) in RCA: 71] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
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Jennings BR, Spach G, Schuster TM. Specific aggregation of poly(?-L-glutamic acid) and hysteresis effects in aqueous solutions. I. Influence of temperature-dependent aggregation on the optical rotation of PGA. Biopolymers 1968. [DOI: 10.1002/bip.1968.360060502] [Citation(s) in RCA: 42] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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