Peptide with built-in conformational constraints: structure of Z-(Aib)7-O
 t
 Bu

Vlassi, Metaxia; Brueckner, Hans; Kokkinidis, Michael

doi:10.1107/s0108768192007171

Cited by 14 publications

(13 citation statements)

References 2 publications

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“…Interestingly, this effect disappears by dilution for Z-(Aib)sOBu/, but not for Z-(Aib)9OBu / (Briickner, unpublished). The crystal structure (Benedetti et aL, 1982) of the pentapeptide shows the typical features of Aib homopeptides (Vlassi et aL, 1993.…”

Section: Structure Of Z-(aib)9obu T Table 3 Average and Selected Bonmentioning

confidence: 94%

“…The two methyl groups attached to C~ are staggered with the methyl groups of residue n + 3 and N--H...O=C main-chain-main-chain hydrogen bonds are formed between residue n + 3 and n. The helical backbone shows the form of a regular triangular rod. In fact, all crystal structures of Aib homopeptides have common properties: centrosymmetric space group, one molecule in the asymmetric unit, a regular 310-helix with the maximum number of hydrogen bonds, including the N-terminal protection group, a reversal of the helical sense at the C-terminal residue and crystal packing in the form of head-to-tail hydrogen-bonded helical columns, most of which pack in an antiparallel fashion (Benedetti et al, 1982;Vlassi et al, 1992;Di Blasio et aL, 1991;Pavone et al, 1991;Vlassi et aL, 1993;Bavoso et al, 1986;Pavone et aL, 1990).…”

Section: Introductionmentioning

confidence: 99%

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Structure of Z-(Aib)₉OBu^t

Geßmann¹,

Brückner²,

Kokkinidis³

1998

Acta Crystallogr Sect B

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The structure of the synthetic protected oligopeptide Z-(Aib)9OBu/, tert-butoxynona(ot-aminoisobutyric acid), which contains the unusual ct-aminoisobutyric acid (Aib), was determined by X-ray crystallography. The two independent molecules in the asymmetric unit fold into 310-helices, each stabilized by seven intramolecular hydrogen bonds. The C terminus of one of the molecules is disordered and adopts a semi-extended conformation, which is rather unusual for Aib residues. This is the first observation of such a conformation involved in a disorder in Aib-containing oligopeptides. The existence of a second conformation for the Cterminal residue might explain the difficulties in crystallizing the title compound and a different behaviour of the title compound in thin layer chromatography compared with the other homopeptides.

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Section: Structure Of Z-(aib)9obu T Table 3 Average and Selected Bonmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Structure of Z-(Aib)₉OBu^t

Geßmann¹,

Brückner²,

Kokkinidis³

1998

Acta Crystallogr Sect B

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“…Protected peptides were characterized by MS, uniformity in TLC, and HPLC. For crystal structures of 1 and 27, see [38] [39]; the ESI-MS of 1 is depicted in Fig. 2.…”

Section: Experimental Partmentioning

confidence: 99%

Studies on the Selective Trifluoroacetolytic Scission of Native Peptaibols and Model Peptides Using HPLC and ESI‐CID‐MS

Theis

Degenkolb

Brückner

2008

Chemistry & Biodiversity

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Representative members of a group of linear, N-acylated polypeptide antibiotics (peptaibols) containing alpha-aminoisobutyric acid (Aib) and, in part, isovaline (Iva), as well as proteinogenic amino acids and a C-terminal-bonded 2-amino alcohol, were treated with anhydrous trifluoroacetic acid (TFA) at 37 degrees for 0.5-26 h. The resulting fragments were separated by HPLC and characterized by electrospray ionization collision-induced dissociation mass spectrometry (ESI-CID-MS). The following 16-20-residue peptaibols were investigated: natural, microheterogeneous mixtures of antiamoebins and alamethicin F50, uniform paracelsin A, and synthetic trichotoxin A50/E. In the natural peptides, bonds formed between Aib (Iva) and Pro (Hyp) were rapidly and selectively cleaved within 0.5 h. Furthermore, TFA esters of the C-terminal amino alcohols were formed. Depending on time, release of C-terminal tri- and tetrapeptides as well as amino acids from the major fragments was observed. Synthetic homooligopeptides, namely Z- and Ac-(Aib)(10)-O(t)Bu and Z-(Aib)(7)-O(t)Bu, were analyzed for comparison. On treatment with TFA, a regular series of Z-(Aib)(10-5)-OH from Z-(Aib)(10)-O(t)Bu were detected within 0.5 h, and, after 3 h, release of a regular series of Z-(Aib)(7-3)-OH from Z-(Aib)(7)-O(t)Bu were observed. Moreover, concomitant release of the series of H-(Aib)(10-3)-OH from the decapeptide occurred. From these data, a repetitive cleavage mechanism via intermediate formation of C-terminal oxazolones on trifluoroacetolysis is proposed. Furthermore, their formation and stability in native peptaibols are correlated with subtle structural differences in protein amino acids linked to Aib. From the conspicuous concordance of the formation and abundance of regular series of trifluoroacetolytic fragments and of positive ions of the b-series in CID-MS, the generation of intermediate oxazolonium ions in both gas and liquid phase is concluded.

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“…These findings lead us to investigate the C-terminal conformation in the long, C-unblocked Aib10. Furthermore, the only structure available of a (Aib) 10 peptide contains the heavy bromine (Z = 35) incorporated at the N-terminus, which was found to affect the crystal packing and hence the resulting structure. This renders the latter structure not comparable with the other homopeptides.…”

Section: Introductionmentioning

confidence: 98%

“…peptaibols) in lipid bilayer membranes [4]. Peptides consisting of only Aib residues show a clear preference for left-handed and right-handed 3 10 -helices in solution and crystal structures. All crystal structures of Aib homopeptides known to date [5][6][7][8][9][10][11][12][13][14] show the following common properties: centrosymmetric space group, regular 3 10 -helices with the maximum number of hydrogen bonds involving also the N-terminal protecting group, head-to-tail hydrogen-bonded columns and a reversal of the helical sense at the C-terminal residue.…”

Section: Introductionmentioning

confidence: 99%

The crystal structure of Z‐(Aib)₁₀‐OH at 0.65 Å resolution: three complete turns of 3₁₀‐helix

Geßmann

Brückner

Petratos

2015

Journal of Peptide Science

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The synthetic peptide Z-(Aib)10-OH was crystallized from hot methanol by slow evaporation. The crystal used for data collection reflected synchrotron radiation to sub-atomic resolution, where the bonding electron density becomes visible between the non-hydrogen atoms. Crystals belong to the centrosymmetric space group P1. Both molecules in the asymmetric unit form regular 310 -helices. All residues in each molecule possess the same handedness, which is in contrast to all other crystal structure determined to date of longer Aib-homopeptides. These other peptides are C-terminal protected by OtBu or OMe. In these cases, because of the missing ability of the C-terminal protection group to form a hydrogen bond to the residue i-3, the sense of the helix is reversed in the last residue. Here, the C-terminal OH-groups form hydrogen bonds to the residues i-3, in part mediated by water molecules. This makes Z-(Aib)10-OH an Aib-homopeptide with three complete 310-helical turns in spite of the shorter length it has compared with Z-(Aib)11-OtBu, the only homopeptide to date with three complete turns.

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Peptide with built-in conformational constraints: structure of Z-(Aib)₇-O^tBu

Cited by 14 publications

References 2 publications

Structure of Z-(Aib)₉OBu^t

Structure of Z-(Aib)₉OBu^t

Studies on the Selective Trifluoroacetolytic Scission of Native Peptaibols and Model Peptides Using HPLC and ESI‐CID‐MS

The crystal structure of Z‐(Aib)₁₀‐OH at 0.65 Å resolution: three complete turns of 3₁₀‐helix

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Peptide with built-in conformational constraints: structure of Z-(Aib)7-O t Bu

Cited by 14 publications

References 2 publications

Structure of Z-(Aib)9OBu t

Structure of Z-(Aib)9OBu t

Studies on the Selective Trifluoroacetolytic Scission of Native Peptaibols and Model Peptides Using HPLC and ESI‐CID‐MS

The crystal structure of Z‐(Aib)10‐OH at 0.65 Å resolution: three complete turns of 310‐helix

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Peptide with built-in conformational constraints: structure of Z-(Aib)₇-O^tBu

Structure of Z-(Aib)₉OBu^t

Structure of Z-(Aib)₉OBu^t

The crystal structure of Z‐(Aib)₁₀‐OH at 0.65 Å resolution: three complete turns of 3₁₀‐helix