Chain Initiation Efficiency in Cobalt- and Nickel-Mediated Polypeptide Synthesis

Deming, Timothy J.; Curtin, Scott

doi:10.1021/ja994281q

Cited by 117 publications

(122 citation statements)

References 21 publications

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“…The block copolypeptide synthesis was performed using the zero valent nickel initiator 2,2′-bipyridyl-Ni(1,5-cyclooctadiene) (BpyNi-COD) [32] to polymerize N e -Z-L-lysine (Z-Lys), Glycine (Gly), and/ or L-Alanine (Ala) NCAs [33] using the procedure developed by Deming [34][35][36]. The details are provided in the Supporting Information.…”

Section: Methodsmentioning

confidence: 99%

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Jan

Shantz

2007

Advanced Materials

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Developing new technologies as a consequence of controlling structure, chemistry, and functionality at the nanometer length scale is the ultimate goal of nanotechnology. One route to this goal is to draw lessons from nature, which has developed the ability to fabricate inorganic and inorganic-hybrid materials such as silica diatoms and nacre that have properties that the materials science community can only aspire to achieve. [1][2][3][4][5][6][7] The development of so-called biomimetic or bioinspired synthesis methods to develop hard matter with new or unusual properties has become an area of tremendous growth. One aspect of this problem is the synthesis of silica materials using amines or polyamines under ambient conditions. Numerous works have demonstrated materials with unusual properties, particularly with respect to morphology and microstructure. [8][9][10][11][12][13][14][15][16][17][18][19][20][21][22][23][24] Of particular relevance to the current work are the numerous reports of silicas made in the presence of poly-L-lysine. From this body of literature it is clear that one can make silicas with various morphologies through manipulation of pH, salt, flow versus quiescent conditions, etc. Further, recent works from several labs have shown the poly-L-lysine chain conformation can be used to control silica morphology. [25,26] It is this point in particular that is explored in the current investigation. Our lab has made two contributions to this blossoming area. First, we have demonstrated that the conformation of polypeptide chains can be used to manipulate the porosity of the oxide obtained. [27,28] Second, we have shown that individual supramolecular objects (vesicles) formed by block copolypeptides can be used as templates to form nanostructured hard materials. [29] In the latter case the block copolypeptides studied were Lys-b-Phe block copolypeptides that form kinetically trapped structures in solution. Here we report the formation of silicas in the presence of a series of block copolypeptides, but mainly Lys-b-Gly block copolypeptides which appear to form more reversible structures as compared to the materials we reported previously. This manuscript reports on how the polypeptide chemistry and solution conditions influence both the morphology and porosity of the hard material they assemble. This latter point has been sparingly studied, yet for many applications this property will be essential. In all cases the block copolypeptides investigated here form supramolecular structures in solution, typically vesicles. However, the Lys-b-Gly block copolypeptides form structures that appear to be more reversible in nature as compared to the objects formed by the Lys-b-Ala and Lys-b-Phe block copolypeptides that appear to be kinetically trapped structures. The critical aggregation concentrations for the polymers studied below are given in the supporting information and are between 0.8-1.7 lM. The syntheses described below use between 3.0-4.0 lM solutions (Methods II, III) or 9.0-10.0 lM solutions (Method I), a...

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Section: Methodsmentioning

confidence: 99%

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Jan

Shantz

2007

Advanced Materials

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“…This ring contraction is thought to occur via migration of an amide proton to the metal-bound carbon, which liberates the chain-end from the metal (Eq. 5) [17]. The resulting amido-amidate complexes were thus proposed as the active polymerization intermediates.…”

Section: Initiators For Transition Metal Catalysismentioning

confidence: 99%

Synthesis and Self-Assembly of Well-Defined Block Copolypeptides via Controlled NCA Polymerization

Deming

2013

Hierarchical Macromolecular Structures: 60 Years After the Staudinger Nobel Prize II

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“…1). 15 The resulting amido-amidate complexes were thus proposed as the active polymerization intermediates. Propagation through the amido-amidate metallacycle was envisioned to occur by initial attack of the nucleophilic amido group on the electrophilic C5 carbonyl of an NCA monomer.…”

Section: Block Copolypeptide Synthesismentioning

confidence: 99%

Preparation and development of block copolypeptide vesicles and hydrogels for biological and medical applications

Deming¹

2014

WIREs Nanomed Nanobiotechnol

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There have been many recent advances in the controlled polymerization of α-amino acid-Ncarboxyanhydride (NCA) monomers into well-defined block copolypeptides. Transition metal initiating systems allow block copolypeptide synthesis with excellent control over number and lengths of block segments, chain length distribution, and chain-end functionality. Using this and other methods, block copolypeptides of controlled dimensions have been prepared and their self-assembly into organized structures studied by many research groups. The ability of well-defined block copolypeptides to assemble into supramolecular copolypeptide vesicles and hydrogels has led to the development of these materials for use in biological and medical applications. These assemblies have been found to possess unique properties that are derived from the amino acid building blocks and ordered conformations of the polypeptide segments. Recent work on the incorporation of active and stimulus responsive functionality in these materials has tremendously increased their potential for use in biological and medical studies.

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Chain Initiation Efficiency in Cobalt- and Nickel-Mediated Polypeptide Synthesis

Cited by 117 publications

References 21 publications

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Biomimetic Silica Formation: Effect of Block Copolypeptide Chemistry and Solution Conditions on Silica Nanostructure

Synthesis and Self-Assembly of Well-Defined Block Copolypeptides via Controlled NCA Polymerization

Preparation and development of block copolypeptide vesicles and hydrogels for biological and medical applications

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