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Two novel series of polyfluorinated amino acids (PFAs) were conceptualized and synthesized as per a very short and scalable synthetic sequence. Results reveal that a short peptide that represents the amino acid sequence of a protein that is recognized by another protein could be tagged with one of the novel PFAs.

Classical molecular dynamics simulations are used to investigate a martensitic-type transformation in crystals of the amino acid DL-norleucine (2-aminohexanoic acid, C[H.sub.3][(C[H.sub.2]).sub.3]CH(H[H.sub.2])COOH). Concerted molecular displacements are considered to be a significant feature of all displacive transformations.

Mass spectrometry is used to observe and analyze the formation of homochiral serine clusters on spontaneous assembly of amino acids into vapor phase, which is a result of the thermal heating of solid compounds in air. The results show that the sublimation of serine under relatively mild conditions leads to the formation of chirally enriched serine octamers, while on the other hand, several cluster-forming chemical reactions can be used to transfer the chiral preference of the starting serine to various other compounds.

The creation of first broad substrate range, nicotinamide cofactor dependent, and highly D-enantio-selective amino acid dehydrogenase is reported. The findings show significant activity toward synthesis of a number of straight, branched and cyclic aliphatic and aromatic D-amino acids.

Competitive experiments with isotopically labeled chorismate derivates have provided direct information about the nature of the transition state of the chorismate mutase reaction both in solution and at the active sites of evolutionarily unrelated enzymes. The competing reaction of chorismate leading to 4-hydroxybenzoate, an intermediate in ubiquinone biosynthesis, likewise appears to occur via an asynchronous concerted mechanism.

A complete and systematic analysis of the relationship between side chain structure and the 14-helicity of a well-studied class of foldamers, beta(super 3)-peptides, in water is reported. The 14-helix propensities of beta(super 3)-amino acids differ starkly from the Alpha-helix propensities of analogous Alpha-amino acids.

Chiral L-amino acids bearing sulfonamide side chains is synthesized, with the tetrahedral sulfonamide groups designed to target bridging coordination interactions with the binuclear manganese cluster in the arginase active site. The results demonstrate that the sulfonamide group is an excellent ligand for the displacement of a hydroxide ion bound to either a single metal ion or a binuclear metal cluster.

A systematic study of aryl radical additions to azomethines that validates the expectation that use of C-N bond would provide a base-free aryl amination method, which is expected to be relatively insensitive to electronic effects, is reported. A more efficient synthetically useful process is the direct addition of aryl radicals to the nitrogen of an azomethine.

An artificial anion receptor is presented, in which two cyclohexapeptide subunits containing l-proline and 6-aminopicolinic acid subunits in an alternating sequence are connected via an adipinic acid spacer. Covalently linking two cyclopeptide molecules derived from 6-aminopicolinic acid subunits with a suitable spacer, an artificial receptor is accessible that strongly binds anions in 50% water/methanol.

The structures and energetics of interactions between aromatic and basic amino acids in alpha-helices are investigated. The results clearly show that each of the five pairs interact favorably when placed i, i + 4 in a helix, with a preference for the aromatic-polar orientation.

A different approach to amino acids based on an expeditious route to enantiopure allylic amines is reported. This is an efficient and general method toward both the L and D configuration of this class of alpha-substituted glycines, as demonstrated by the synthesis of N-protected L and D (1-adamantyl)-glycines.

Complete synthesis of the vancomycin requires that stereogenic axes be formed in a stereoselective manner for which an atropselective variation of the triazine mediated-diaryl ether forming reaction is developed. An atropselective macrocyclization reaction that lead to a single atropisomer of a cyclopeptide diaryl ether related to the ring system of vancomycin was enforced through placement of a substituent on the aromatic ring of tyrosine residue.

The mode of metal ion and water binding to the amino acid valine is investigated. The results indicate that metal ion in the lithiated and sodiated clusters is NO-coordinated to nonzwitterionic valine and in potassiated cluster has OO coordination.

The synthesis of teicoplanin aglycon is carried out from peptidic subunits to incorporate lack of the amino acid subunits in their correct oxidation states. The high site selectivity and yield of amide deprotection sequence demonstrates that amidic protection of carboxylic acids is a viable strategy for complex molecules containing multiple amides.

A novel Pd(II)-catalyzed ortho-C-H olefination protocol is developed by using spatially remote, unprotected tertiary, secondary and primary alcohols as the directing groups. Mono-N-protected amino acid ligands have promoted the reaction and an array of olefin coupling partners is used.

A combination of aromatic amino acid, a homoserine side chain and a D-amine acid is used for designing a series of linear tetrapeptides that has adopted a 'Hse turn' in water. The conformation is stabilized by intramolecular hydrogen bonds and the peptide with sequence H-Abz-Homoser-Ser-D-Gln-N[H.sub.2] has showed major through-space interactions.

The integration of ring-opening metathesis polymerization (ROMP) and ring-opening polymerization of the amino acid N-carboxyanhydride (NCA) is described that has allowed the facile synthesis of brush-like polymers containing polypeptide as the brush side chains. Brush-like poly(norbornene)s with grafted polypeptides or block copolypeptides are obtained with controlled molecular weights and narrow molecular weight distributions.

Several experiments are carried out to determine the relative rates of reaction and the relative reactivity of the various free and N-acetyl [alpha]-amino acids. The results prove that the backbone and adjacent side chain positions of amino acids are extremely resistant to hydrogen atom transfer, hence making them capable of avoiding degradation in Nature.

The article presents a newly developed approach that can be used for the formation of chiral catalysts with high enantioinduction. It is proved that several different chiral environments with different amino acids or ligands can be formed by the discussed method.

The synthesis of amino acid derived norbornene monomers having carboxy and amino groups were performed and subjected to ring-opening metathesis copolymerization with various feed ratios using the Grubbs second generation ruthenium catalyst. The results obtained provide insight into the alternating copolymerization brought about by the acid-base interaction between the monomers and/or between the propagating polymer end and the incoming monomer.

A design is described that is based on the application of configurationally unstable stereogenic nitrogen, which has played a major role in setting up the stereochemical match between the three stereogenic centers in the corresponding products.

NMR relaxation dispersion methods are used for observing the dynamic process through which the KIX domain of CREB binding protein communicates allosteric information between binding sites. The dynamic NMR data has disclosed that an evolutionarily conserved network of hydrophobic amino acids has constituted the pathway through which information is transmitted.

A metal-ion chelating amino acid ((8-hydroxyquinolin)-3-yl)alanine) is genetically encoded in Escherichia coli by an amber nonsense codon and corresponding orthogonal tRNA/aminoacyl-tRNA synthetase pair. The structure has showed a high occupancy of the heavy metal bound to the HQ-Ala residue and this method has facilitated the de novo design of metalloproteins with novel structures and functions, including fluorescence sensors.

The [super 13]C[alpha] chemical shift tensors are obtained for each amino acid in the protein GB1. The resulting structures have precision and accuracy, thus providing a way for using both isotropic and anisotropic chemical shift results in the de novo determination of high accuracy, solid-state protein structures.

The evolution of total enantioenrichment of the solid phase is described for an essential amino acid mediated by solution-phase racemization. The results have shown that the emergence of a state of solid-phase single chirality for a proteinogenic amino acid is achieved in a near equilibrium process even in the absence of mechanical energy input leading to enhanced attrition of crystals.

The enantioselective total synthesis of clavirolide C is described, which has featured the application of chiral amino acid based ligands in Cu-catalyzed asymmetric conjugate addition (ACA) reactions and a Ru-catalyzed ring-closing metathesis (RCM). The results have pointed towards the unresolved problem of identifying a stereoselective method for aldol additions involving cyclic enol ethers adjacent to quaternary stereogenic centers.

A revised structure is described for methanobactin (mb), which has reconciled chemical analysis, NMR, X-ray and mass spectrometry data with possible biosynthetic pathways for expression of mb in bacteria. The new revised mb structure has suggested possible pathways for the biosynthesis of mb from common amino acids.

Enantioselective indicator displacement assays (eIDAs) are implemented by the use of two chiral receptors in conjunction with the indicator chrome azurol S. The method has used a conventional ultraviolet (UV)-visible (vis) spectrophotometer to monitor the colorimetric signal, which has allowed a potential high-throughput screening (HTS) method for determining enantiomeric excess (ee).

A direct catalytic and highly diastereo- and enantioselective approach is described for protected syn [beta]-hydroxy-[alpha]-amino acids by using a bifunctional thiourea catalyst that has operated under mild reaction conditions. Low catalyst loadings and operationally convenient conditions have made this method attractive for preparing various protected syn [beta]-hydroxy-[alpha]-amino acids.

The effects of the identity of N-terminal residues on the product distribution generated upon reaction with pyridoxal 5'-phosphate (PLP) are examined. The results have shown that optimal product conversion might be attained using slightly different reaction conditions, which might vary based on the identity of the substrate at hand.

Artificial molecular clips and tweezers, designed for cofactor and amino acid recognition, have inhibited the enzymatic activity of alcohol dehydrogenase (ADH). The complexes of ADH with clips and tweezer are visualized in a nondenaturing gel electrophoresis and hence supramolecular chemistry is used as a means to control protein function.

Alkylations of pyridyl-substituted ynones with [Et.sub.2]Zn and [Me.sub.2]Zn, promoted by amino acid-based chiral ligands in the presence of Al-based alkoxides, have afforded tertiary propargyl alcohols. Enantioerically enriched tertiary alcohols bearing a pyridyl and an alkyne substituent is functionalized in a variety of manners to furnish a wide range of difficult to-access acyclic and heterocyclic structures.

Three different nuclear magnetic resonance (NMR)-active unnatural amino acids are incorporated with high efficiency at different sites in a 33 kDa protein of pharmaceutical interest without adversely affecting protein structure and ligand binding. [super 13]C-labeled methyl groups introduced with the unnatural amino acid is shown to be advantageous for studying a large protein.

The structural and dynamical differences between oxidized and reduction forms of amyloid-[beta] peptides composed of 42 amino acids ([A[beta]42.sup.ox] and [A[beta]42.sup.red]) monomers are examined by using solution NMR. The studies have disclosed that M35 oxidation of A[beta]42 has induced A[beta]40-like structural and dynamical changes by preventing the G37-G38 turn conformation, which has contributed to its reduced aggregation and toxicity.

An original Hadamard-based sign-encoding scheme is described for differentiating among seven amino acid groups from a single experiment that can be performed in a very short acquisition time. This method is suitable for automation, as a single [super 1]H, [super 15]N frequency list.

A sector map based on first-principles computations was developed to study the correspondence between circular dichroism and optical rotation for zwitterrionic and protonated L-amino acid chromophores. The findings from the computations of 12 amino acids help to obtain accurate Clough, Lutz, and Jirgensons (CLJ) effect.

Pulsed ionization high-pressure mass spectrometry (HPMS) and ab initio calculations are used for studying the thermochemistry of gas-phase ion-molecule interactions and structures of many clusters formed between protonated amino acids and either ammonia or amines. The organic ammonium ions have effectively stabilized the zwitterionic structure of amino acids, even more effectively than metal ions.

A new approach for the preparation of designed amino acid atom transfer radical polymerization (ATRP) initiators for the synthesis of various biohybrid materials is discussed.

Several experiments are conducted to study the conformational manifold of [alpha]-aminoisobutyric acid (Aib) containing alanine-based tripeptides in an aqueous solution. All the peptides in the acid are found to exhibit multiple conformations.

Several potent, highly selective macrocyclic inhibitors of amino acid adenylation domain that do not inhibit the non-ribosomal peptide (RNA) synthetases are developed. The amino acid adelyation exhibit high structural homology and hence can be inhibit other domains to provide a broad spectrum for various biological and therapeutic applications.

The unnatural nanometer-sized amino acids are introduced as the nanometer-length building blocks for the synthesis of water-soluble molecular rods of precise lengths that can exceed at least up to ten nanometers. The building block is extremely compatible with the standard solid-phase peptide synthetic techniques, providing completely water soluble peptides.

A minimal ring-closing metathesis reaction (RCM) constraint for the [3.sub.10]-helix is developed, which is a relatively common structural motif in proteins and peptides containing [C.sup.[alpha]]-tetrasubstituted [alpha]-amino acids. It is shown that a minimal, RCM-derived, macrocyclic constraint can be incorporated into [3.sub.10]-helical peptides.

A [beta]-dodecapeptide (Zwit-IF) that self-assembles spontaneously in aqueous solution into a highly thermostable [beta]-peptide octamer is examined to determine its structure. The Zwit-IF structure is remarkably protein-like composed of a discrete number of helices and possesses a solvent-excluded hydrophobic core.

A qualitative assessment of the relative strengths of hydrogen bonds involving phosphorylated amino acid side chains (pSer, pAsp) is carried out. It is seen that Arg is capable of substantially strong bridges with phosphorylated side chains than Lys and a pSer hydrogen bond acceptor has the tendency to form more stable interaction than a pAsp acceptor.

Some simple and efficient routes to highly enantiomerically enriched anti-1,2-amino alcohols and syn-1,2-diols through direct asymmetric Mannich, Mannich-type, and aldol reactions involving unmodified alpha-hydroxyketones catalyzed by primary amine-containing amino acids are described. The findings present additional support for the hypothesis suggesting that amino acid catalysis played a key role in prebiotic chemistry facilitating the asymmetric synthesis of the molecules of life.

The L-type amino acid transporter LAT1 that is highly over expressed in some tumor cell lines takes up lipophilic and neutral amino acids. A variety of natural and artificial amino acids such as iodinated phenylalanine and tyrosine analogues, the anticancer drug melphalan, and even BCH are efficiently transported by the LAT system.

The spontaneous resolution of racemic mixtures is rarely observed in nature but research work shows that a few amino acids resolve as small clusters because of unique structural characteristics. A family of larger praline clusters produced by electrospray ionization that form extended rodlike geometrics show evidence for spontaneous enantiomeric enrichment.

The chemistry of 3,4-dihydroxylphenylalanine (DOPA)-protein cross-linking is reported. The results have indicated that DOPA-protein cross-linking and 1,2-diol oxidative cleavage proceeds through different mechanisms and that carbohydrates would not interfere with this process when carried out in crude cell extracts or on intact cells.

An excellently designed polycholesteryl substituted cyclen complex host molecule was employed and the successful inversion of enantioslectivity in molecular recognition controlled by lateral pressure applied to the monolayer at the air-water interface is described. It was seen that at the air-water interface chiral recognition was proven to be more strongly modulated than in solutions and a small difference in the amino acid structure resulted in differing selectivities.

A pair of short [beta]-peptides that assemble noncovalently into a well-defined quaternary structure characterized by an integral stoichiometry, highly stabilized secondary structure, and a cooperative melting transition is described. The predominance at equilibrium of both homo- and heterodimers, irrespective of the directional approach to equilibrium, suggest a hetero-oligomer composed of both parallel and antiparallel helices.