19 research outputs found
Parámetros de control glucémico en pacientes con diabetes tipo 2 no insulinizados derivados a consulta de Endocrinología, y grado de implementación del consenso nacional sobre el tratamiento de la hiperglucemia
Jerusalem in Naḥmanides's Religious Thought: The Evolution of the “Prayer over the Ruins of Jerusalem”
Bioabsorbable zinc ion induced biphasic cellular responses in vascular smooth muscle cells
A Novel Liver X Receptor Agonist Establishes Species Differences in the Regulation of Cholesterol 7α-Hydroxylase (CYP7a)
Amyloidogenic sequences in native protein structures
Numerous short peptides have been shown to form β-sheet amyloid aggregates in vitro. Proteins that contain such sequences are likely to be problematic for a cell, due to their potential to aggregate into toxic structures. We investigated the structures of 30 proteins containing 45 sequences known to form amyloid, to see how the proteins cope with the presence of these potentially toxic sequences, studying secondary structure, hydrogen-bonding, solvent accessible surface area and hydrophobicity. We identified two mechanisms by which proteins avoid aggregation: Firstly, amyloidogenic sequences are often found within helices, despite their inherent preference to form β structure. Helices may offer a selective advantage, since in order to form amyloid the sequence will presumably have to first unfold and then refold into a β structure. Secondly, amyloidogenic sequences that are found in β structure are usually buried within the protein. Surface exposed amyloidogenic sequences are not tolerated in strands, presumably because they lead to protein aggregation via assembly of the amyloidogenic regions. The use of α-helices, where amyloidogenic sequences are forced into helix, despite their intrinsic preference for β structure, is thus a widespread mechanism to avoid protein aggregation