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del Pozo-Yauner L, Wall JS, González Andrade M, Sánchez-López R, Rodríguez-Ambriz SL, Pérez Carreón JI, Ochoa-Leyva A, Fernández-Velasco DA. The N-terminal strand modulates immunoglobulin light chain fibrillogenesis. Biochem Biophys Res Commun 2013; 443:495-9. [PMID: 24321098 DOI: 10.1016/j.bbrc.2013.11.123] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2013] [Accepted: 11/27/2013] [Indexed: 12/20/2022]
Abstract
It has been suggested that the N-terminal strand of the light chain variable domain (V(L)) protects the molecule from aggregation by hindering spurious intermolecular contacts. We evaluated the impact of mutations in the N-terminal strand on the thermodynamic stability and kinetic of fibrillogenesis of the V(L) protein 6aJL2. Mutations in this strand destabilized the protein in a position-dependent manner, accelerating the fibrillogenesis by shortening the lag time; an effect that correlated with the extent of destabilization. In contrast, the effect on the kinetics of fibril elongation, as assessed in seeding experiments was of different nature, as it was not directly dependant on the degree of destabilization. This finding suggests different factors drive the nucleation-dependent and elongation phases of light chain fibrillogenesis. Finally, taking advantage of the dependence of the Trp fluorescence upon environment, four single Trp substitutions were made in the N-terminal strand, and changes in solvent exposure during aggregation were evaluated by acrylamide-quenching. The results suggest that the N-terminal strand is buried in the fibrillar state of 6aJL2 protein. This finding suggest a possible explanation for the modulating effect exerted by the mutations in this strand on the aggregation behavior of 6aJL2 protein.
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Affiliation(s)
- Luis del Pozo-Yauner
- Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610, Mexico.
| | - Jonathan S Wall
- Departments of Radiology and Medicine, The University of Tennessee Medical Center, 1924 Alcoa Highway, Knoxville, TN, USA
| | - Martín González Andrade
- Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610, Mexico
| | - Rosana Sánchez-López
- Instituto de Biotecnología, Universidad Nacional Autónoma de México, Av. Universidad #2001, Col. Chamilpa Cuernavaca, Morelos C.P. 62210, Mexico
| | - Sandra L Rodríguez-Ambriz
- Centro de Desarrollo de Productos Bióticos, Instituto Politécnico Nacional, Calle CEPROBI No. 8, Col. San Isidro, Yautepec, Morelos C.P. 62731, Mexico
| | - Julio I Pérez Carreón
- Instituto Nacional de Medicina Genómica, Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan, México, D.F. C.P. 14610, Mexico
| | - Adrián Ochoa-Leyva
- Unidad de Genómica de Poblaciones Aplicada a la Salud, Facultad de Química, UNAM-Instituto Nacional de Medicina Genómica (INMEGEN), Periférico Sur No. 4809, Col. Arenal Tepepan, Delegación Tlalpan México, D.F. C.P. 14610, Mexico
| | - D Alejandro Fernández-Velasco
- Laboratorio de Fisicoquímica e Ingeniería de Proteínas, Departamento de Bioquímica, Facultad de Medicina, Universidad Nacional Autónoma de México, Circuito Interior, Ciudad Universitaria, Av. Universidad 3000, México, D.F. C.P. 04510, Mexico
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Abstract
The social conformity paradigm of Asch (1956) was replicated to investigate the relationship between age and conformist behavior. One hundred ten Australian school children and adolescents between 3 and 17 years of age participated in the study. Each participant was placed in the position of being a minority of 1 against a wrong but unanimous majority of 3. The results indicate that conformity decreases with age in perceptually unambiguous tasks. Conflicting evidence from earlier studies can be attributed to task ambiguity in those studies.
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Affiliation(s)
- M B Walker
- Department of Psychology, University of Sydney, NSW, Australia
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