2,8-Dimethyl-4-(carboxymethyl)-6-(aminomethyl)phenoxathiin S-dioxide: an organic substitute for the .beta.-turn in peptides?

1986 ◽  
Vol 108 (1) ◽  
pp. 181-182 ◽  
Author(s):  
Martin. Feigel
Keyword(s):  
Beta Turn

scholarly journals Single-Residue Changes in the C-Terminal Disulfide-Bonded Loop of the Pseudomonas aeruginosa Type IV Pilin Influence Pilus Assembly and Twitching Motility

2009 ◽  
Vol 191 (21) ◽  
pp. 6513-6524 ◽  
Author(s):  
Hanjeong Harvey ◽  
Marc Habash ◽  
Francisca Aidoo ◽  
Lori L. Burrows
Keyword(s):  
Pseudomonas Aeruginosa ◽  
Antigenic Variation ◽  
Intact Protein ◽  
Twitching Motility ◽  
Beta Turn ◽  
Type Iv ◽  
Pilin Subunit ◽  
Type Iv Pilin ◽  
Intersubunit Interactions ◽  
Pilus Assembly

ABSTRACT PilA, the major pilin subunit of Pseudomonas aeruginosa type IV pili (T4P), is a principal structural component. PilA has a conserved C-terminal disulfide-bonded loop (DSL) that has been implicated as the pilus adhesinotope. Structural studies have suggested that DSL is involved in intersubunit interactions within the pilus fiber. PilA mutants with single-residue substitutions, insertions, or deletions in the DSL were tested for pilin stability, pilus assembly, and T4P function. Mutation of either Cys residue of the DSL resulted in pilins that were unable to assemble into fibers. Ala replacements of the intervening residues had a range of effects on assembly or function, as measured by changes in surface pilus expression and twitching motility. Modification of the C-terminal P-X-X-C type II beta-turn motif, which is one of the few highly conserved features in pilins across various species, caused profound defects in assembly and twitching motility. Expression of pilins with suspected assembly defects in a pilA pilT double mutant unable to retract T4P allowed us to verify which subunits were physically unable to assemble. Use of two different PilA antibodies showed that the DSL may be an immunodominant epitope in intact pili compared with pilin monomers. Sequence diversity of the type IVa pilins likely reflects an evolutionary compromise between retention of function and antigenic variation. The consequences of DSL sequence changes should be evaluated in the intact protein since it is technically feasible to generate DSL-mimetic peptides with mutations that will not appear in the natural repertoire due to their deleterious effects on assembly.

scholarly journals An Elastin-Derived Self-Assembling Polypeptide

2013 ◽  
Vol 2013 ◽  
pp. 1-7 ◽  
Author(s):  
Antonietta Pepe ◽  
Brigida Bochicchio
Keyword(s):  
Elastic Properties ◽  
Matrix Protein ◽  
Extracellular Matrix Protein ◽  
Elastic Fibers ◽  
Hydrophobic Region ◽  
Beta Turn ◽  
Self Assembling ◽  
Polypeptide Sequence ◽  
Hydrophilic Region ◽  
Self Aggregation

Elastin is an extracellular matrix protein responsible for the elastic properties of organs and tissues, the elastic properties being conferred to the protein by the presence of elastic fibers. In the perspective of producing tailor-made biomaterials of potential interest in nanotechnology and biotechnology fields, we report a study on an elastin-derived polypeptide. The choice of the polypeptide sequence encoded by exon 6 of Human Tropoelastin Gene is dictated by the peculiar sequence of the polypeptide. As a matter of fact, analogously to elastin, it is constituted of a hydrophobic region (GLGAFPAVTFPGALVPGG) and of a more hydrophilic region rich of lysine and alanine residues (VADAAAAYKAAKA). The role played by the two different regions in triggering the adoption of beta-turn and beta-sheet conformations is herein discussed and demonstrated to be crucial for the self-aggregation properties of the polypeptide.

scholarly journals Type I beta-turn conformation is important for biological activity of the melanocyte-stimulating hormone analogues

1999 ◽  
Vol 265 (1) ◽  
pp. 430-440 ◽  
Author(s):  
Song-Zhe Li ◽  
Jung-Hoon Lee ◽  
Weontae Lee ◽  
Chang-Ju Yoon ◽  
Ja-Hyun Baik ◽  
...  
Keyword(s):  
Biological Activity ◽  
Type I ◽  
Beta Turn ◽  
Melanocyte Stimulating Hormone ◽  
Stimulating Hormone

scholarly journals Adaptation of the Romanomermis culicivorax CCA-Adding Enzyme to Miniaturized Armless tRNA Substrates

2020 ◽  
Vol 21 (23) ◽  
pp. 9047
Author(s):  
Oliver Hennig ◽  
Susanne Philipp ◽  
Sonja Bonin ◽  
Kévin Rollet ◽  
Tim Kolberg ◽  
...  
Keyword(s):  
Mitochondrial Genome ◽  
Weak Interaction ◽  
Substrate Affinity ◽  
Catalytic Core ◽  
Beta Turn ◽  
Human Enzyme ◽  
Human Counterpart ◽  
Core Elements ◽  
Trna Primer

The mitochondrial genome of the nematode Romanomermis culicivorax encodes for miniaturized hairpin-like tRNA molecules that lack D- as well as T-arms, strongly deviating from the consensus cloverleaf. The single tRNA nucleotidyltransferase of this organism is fully active on armless tRNAs, while the human counterpart is not able to add a complete CCA-end. Transplanting single regions of the Romanomermis enzyme into the human counterpart, we identified a beta-turn element of the catalytic core that—when inserted into the human enzyme—confers full CCA-adding activity on armless tRNAs. This region, originally identified to position the 3′-end of the tRNA primer in the catalytic core, dramatically increases the enzyme’s substrate affinity. While conventional tRNA substrates bind to the enzyme by interactions with the T-arm, this is not possible in the case of armless tRNAs, and the strong contribution of the beta-turn compensates for an otherwise too weak interaction required for the addition of a complete CCA-terminus. This compensation demonstrates the remarkable evolutionary plasticity of the catalytic core elements of this enzyme to adapt to unconventional tRNA substrates.

Synthesis, conformational properties, and antibody recognition of peptides containing .beta.-turn mimetics based on .alpha.-alkylproline derivatives

1991 ◽  
Vol 34 (6) ◽  
pp. 1777-1789 ◽  
Author(s):  
Mark G. Hinds ◽  
John H. Welsh ◽  
David M. Brennand ◽  
J. Fisher ◽  
Martin J. Glennie ◽  
...  
Keyword(s):  
Beta Turn ◽  
Antibody Recognition ◽  
Conformational Properties
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