<i>tert</i>-Butoxycarbonyl-<scp>L</scp>-leucyl-<scp>L</scp>-threoninamide

Banumathi, S.; Velmurugan, D.; Subramanian, E.; Ashish, N.; Kishore, Raghuvansh

doi:10.1107/s0108270198010385

Cited by 6 publications

(7 citation statements)

References 1 publication

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“…The two motifs discussed above were found to occur together in the peptide, Boc-Leu-Thr-NH 2 (where Boc = t -butoxycarbonyl group) 16 (also unpublished data) ( Fig. 1c providing an equivalent fused five-membered rings motif seen in protein structures).…”

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confidence: 71%

A novel secondary structure based on fused five-membered rings motif

Dhar

Kishore

Chakrabarti

2016

Sci Rep

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An analysis of protein structures indicates the existence of a novel, fused five-membered rings motif, comprising of two residues (i and i + 1), stabilized by interresidue Ni+1–H∙∙∙Ni and intraresidue Ni+1–H∙∙∙O=Ci+1 hydrogen bonds. Fused-rings geometry is the common thread running through many commonly occurring motifs, such as β-turn, β-bulge, Asx-turn, Ser/Thr-turn, Schellman motif, and points to its structural robustness. A location close to the beginning of a β-strand is rather common for the motif. Devoid of side chain, Gly seems to be a key player in this motif, occurring at i, for which the backbone torsion angles cluster at ~(−90°, −10°) and (70°, 20°). The fused-rings structures, distant from each other in sequence, can hydrogen bond with each other, and the two segments aligned to each other in a parallel fashion, give rise to a novel secondary structure, topi, which is quite common in proteins, distinct from two major secondary structures, α-helix and β-sheet. Majority of the peptide segments making topi are identified as aggregation-prone and the residues tend to be conserved among homologous proteins.

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confidence: 71%

A novel secondary structure based on fused five-membered rings motif

Dhar

Kishore

Chakrabarti

2016

Sci Rep

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“…The side-chain conformation of the Thr residue can be described by the torsion angles 1 1,1 (N1ÐC1ÐC5ÐC6) and 1 1,2 (N1ÐC1ÐC5ÐO4) and is of (g À g + ) type in both structures (Tables 1 and 3). This conformation with the hydroxyl group in gauche + conformation dominates over the (tg À ) one in peptide structures (Benedetti et al, 1983;Doi et al, 1993;Banumathi et al, 1999) and is the most favoured according to conformational energy calculations (Vasquez et al, 1983).…”

Section: Commentmentioning

confidence: 98%

AmmoniumN-acetyl-L-threoninate and methylammoniumN-acetyl-L-threoninate

Puliti¹,

Mattia²

2000

Acta Crystallogr C

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“…32,33 As one of our series of investigations, we have been involved in designing biologically relevant unusual foldedunfolded structural features in Thr containing homochiral or heterochiral model peptides of the type Boc-Aaa-Thr-OMe, where Aaa may be a proteinogenic or nonproteinogenic a-amino acid. 28,32,[34][35][36][37] We previously reported, using X-ray diffraction analysis and 1 H NMR spectroscopy, the characterization of a novel Asx-turns like motif in terminally blocked homochiral peptides Boc-Thr-Thr-OMe and Boc-Thr-Thr-NH 2 , stabilized by an unconventional main-chain to sidechain C c À ÀH. .…”

Section: Introductionmentioning

confidence: 99%

Intramolecular CH···O Hydrogen‐bond mediated stabilization of a Cis‐DPro imide‐bond in a stereocontrolled heterochiral model peptide

Bhadbhade

Kishore

2011

Biopolymers

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The X-ray diffraction analysis of a stereocontrolled heterochiral designed model peptide Boc-(D) Pro-Thr-OMe (1) revealed the existence of an unusual folded molecular structure, stabilized via an effective unconventional C---H…O type intramolecular hydrogen-bond, encompassing a noncovalent 12-membered ring-motif. Together with an uncommon type a disposition of the urethane moiety, the tightly folded topology is compounded with a cis-(D) Pro imide-bond. The overall conformation is suggested to be the reminiscent of specific type VI β-turn structures, hitherto, characterized across the Aaa-cis-Pro peptide-bonds in globular proteins and polypeptides. The (13) C NMR spectrum of 1 in an apolar CDCl(3) environment revealed the presence of approximately an equal population of cis and trans isomers unexpectedly, analogous to Pro side-chain, the (13) C NMR chemical-shifts of Thr C(β) -resonance is observed to be sensitive toward cis-trans isomerization. In conjunction with solid-state FT-IR spectral data, we established that a network of complex intermolecular hydrogen-bonds stabilize a self-complementary noncovalent helical hexagonal self-assembly and crystallographic supramolecular aggregate. The results incline us to highlight that the stabilization of cis-(D) Pro peptide-bond in crystalline state may be driven by the favorable energy of formation of an unconventional weak C---H…O intramolecular hydrogen-bond.

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tert-Butoxycarbonyl-L-leucyl-L-threoninamide

Cited by 6 publications

References 1 publication

A novel secondary structure based on fused five-membered rings motif

A novel secondary structure based on fused five-membered rings motif

AmmoniumN-acetyl-L-threoninate and methylammoniumN-acetyl-L-threoninate

Intramolecular CH···O Hydrogen‐bond mediated stabilization of a Cis‐DPro imide‐bond in a stereocontrolled heterochiral model peptide

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