Microchemical structural determination of a peptoid covalently bound to a polymeric bead by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

Zambias, Robert A.; Boulton, D. A.; Griffin, Patrick R.

doi:10.1016/s0040-4039(00)73334-x

Cited by 60 publications

(28 citation statements)

References 7 publications

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“…[9][10][11]; (ii) spatially addressable syntheses in which the structure of a compound is deduced from its position on an array (2,(12)(13)(14); and (iii) split synthesis procedures, whereby compounds are built up on solid-phase beads, each of which has a unique history throughout the randomization steps and hence a unique structure-e.g., "one-bead-one-peptide" (4,6). The appropriate synthetic strategies can be modified in a number of ways so that with each component introduced by a combinatorial step, a conjugate "tag" is added in a parallel step; these coding sequences or tags are read subsequently to decode the steps used for the construction of the structure on any given bead.…”

mentioning

confidence: 99%

Enzyme-mediated spatial segregation on individual polymeric support beads: application to generation and screening of encoded combinatorial libraries.

Vagner

Bárány

Lam

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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Proteolysis of short NO-protected peptide substrates bound to polyoxyethylene-polystyrene beads releases selectively free amino sites in the enzyme-accessible "surface" area, The substantial majority of functional sites in the "interior" of the polymeric support are not reached by the enzyme and remain uncleaved (protected). Subsequent synthesis with two classes of orthogonal protecting groupsNa_tert-butyloxycarbonyl (Boc) and Na_9-fluorenylmethyloxycarbonyl (Fmoc)-allows generation of two structures on the same bead. The surface structure is available for receptor interactions, whereas the corresponding interior structure is used for coding. Coding structures are usually readily sequenceable peptides. This "shaving" methodology was illustrated by the preparation of a peptide-encoded model peptide combinatorial library containing 1.0 x 105 members at -6-fold degeneracy. From this single library, good ligands were selected for three different receptors: anti-.8-endorphin antibody, streptavidin, and thrombin, and the binding structures were deduced correctly by sequencing the coding peptides present on the same beads.

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mentioning

confidence: 99%

Enzyme-mediated spatial segregation on individual polymeric support beads: application to generation and screening of encoded combinatorial libraries.

Vagner

Bárány

Lam

et al. 1996

Proc. Natl. Acad. Sci. U.S.A.

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“…4 Cleavage of the covalent bond between the loaded organic structure and the polymeric support upon TOF-SIMS bombardment was found to produce ions featuring the anchored molecule. 3,4,10,11 The release of the synthesized compounds in solution by chemical 12 or photochemical 13 treatments prior to electrospray ionization (ESI) or matrixassisted laser desorption/ionization (MALDI) mass spectrometric analyses is not required. Time consuming steps and wasted materials are thus avoided providing rapid and efficient analyses.…”

Section: Discussionmentioning

confidence: 99%

Time-of-flight secondary ion mass spectrometry of Fmoc-amino acids linked to solid supports through ionic interactions

Enjalbal¹,

Martínez²,

Subra³

et al. 1998

Rapid Commun. Mass Spectrom.

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The TOF-SIMS (time-of-flight-secondary ion mass spectrometry) spectra of Fmoc-amino acids linked to solid supports through ionic interactions have been studied to examine if easy desorption of preformed ions from the surface occurred. Preliminary results indicated that the structure of the polymer affected the nature of the recovered ions. However, in the case of widely used polystyrene based supports, characteristic ions of the amino acids were clearly observed with noticeable abundances. Moreover, an analytical criterion to differentiate Fmoc-amino acids linked to various solid supports through either covalent or ionic bonds was established. # 1998 John Wiley & Sons, Ltd. Received 9 September 1998; Accepted 9 September 1998 Very few spectroscopic methods are available to analyze samples in the solid state whereas such techniques present numerous applications in the fast-growing field of solidphase chemistry. Indeed, rapid and efficient product characterization should be obtained with the organic moieties still anchored to the support, thus avoiding product release in solution by any time-consuming and eventually deleterious chemical treatments.Cross polarization-magic angle spinning (CP-MAS) NMR 1 and IR 2 have been used to follow polymer supported syntheses but the main drawback of such techniques consists of the overlapping of the polymer signals with the signals of the expected compound.We have developed an alternative analytical method based on time-of-flight-secondary ion mass spectrometry (TOF-SIMS) to monitor step by step solid-phase peptide syntheses. 3,4 We report the results obtained when this technique was applied to samples where the amino acids were not covalently linked as previously described but simply anchored onto various supports through ionic interactions. EXPERIMENTAL ChemicalsProtected amino acids and the MBHA-resin were purchased from Senn Chemicals AG (Germany). The pin support consists of a derivatized crown, upon which synthesis is performed, and an inert polypropylene stem. The aminomethylated polystyrene-grafted (PS-pin) and methacrylic acid/dimethylacrylamide-grafted (MD-pin) crowns were supplied by Chiron Technologies Pty. Ltd. (Australia). The crowns and the resin which bear free amino groups were immersed overnight in a 0.4 M dimethylformamide (DMF) solution of Fmoc-protected amino acid (either Fmoc-Phe-OH or Fmoc-Leu-OH) and then washed once with DMF for 1 minute. Mass spectrometryCrown samples analyzed by TOF-SIMS were cut out directly from the the pins with a razor blade to obtain thin slices, which were then immediately placed on a stainless grid. The resin beads were analyzed directly, as such. TOF-SIMS measurements were performed on a TRIFT I spectrometer from the PHI-Evans Company (Eden-Prairie, MN, USA). Spectra were recorded using a pulse (1 ns, 12 kHz) liquid metal source ( 69 Ga, 15 keV) operating in the bunched mode of operation in order to provide good mass resolution (m/Dm = 2000, measured at m/z 43). Due to large charging effects on the insulating materials pres...

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“…While it is possible to synthesize mixtures of small molecules each in a tiny amount, determining the identity of ''winners'' is accomplished by a process of deconvolution rather than encoding. [This is because the only code in such a library is chemical identity, and at such tiny amount the only tool useful to establish identity is mass spectrometry (3)(4)(5)(6)(7)(8).] Instead, such small molecule libraries are produced on polymer beads, each bead possessing only one type of molecule (9).…”

Section: Encoding Strategies In Combinatorial Chemistrymentioning

confidence: 99%

Encoding strategies in combinatorial chemistry

Czarnik

1997

Proc. Natl. Acad. Sci. U.S.A.

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Microchemical structural determination of a peptoid covalently bound to a polymeric bead by matrix-assisted laser desorption ionization time-of-flight mass spectrometry

Cited by 60 publications

References 7 publications

Enzyme-mediated spatial segregation on individual polymeric support beads: application to generation and screening of encoded combinatorial libraries.

Enzyme-mediated spatial segregation on individual polymeric support beads: application to generation and screening of encoded combinatorial libraries.

Time-of-flight secondary ion mass spectrometry of Fmoc-amino acids linked to solid supports through ionic interactions

Encoding strategies in combinatorial chemistry

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