Cavity filling mutations at the thyroxine-binding site dramatically increase transthyretin stability and prevent its aggregation.
More than a hundred different Transthyretin (TTR) mutations are associated with fatal systemic amyloidoses. They destabilize the protein tetrameric structure and promote the extracellular deposition of TTR as pathological amyloid fibrils. So far, only mutations R104H and T119M have been shown to stabilize significantly TTR, acting as disease suppressors. We describe a novel A108V non-pathogenic mutation found in a Portuguese subject. This variant is more stable than wild type TTR both in vitro and in human plasma, a feature that prevents its aggregation. The crystal structure of A108V reveals that this stabilization comes from novel intra and inter subunit contacts involving the thyroxine (T4) binding site. Exploiting this observation, we engineered a A108I mutation that fills the T4binding cavity, as evidenced in the crystal structure. This synthetic protein becomes one of the most stable TTR variants described so far, with potential application in gene and protein replacement therapies.
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.|Instituto de Bioquímica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Ricardo
R
Sant'Anna
i3S - Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.|ICBAS, Instituto de Ciências Biomédicas Abel Salazar, Universidade do Porto, Rua Jorge Viterbo Ferreira 228, 4050 - 313 Porto, Portugal.
Maria Rosário
MR
Almeida
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.|Instituto de Bioquímica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Nathalia
N
Varejāo
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Pablo
P
Gallego
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Sebastian
S
Esperante
Instituto de Bioquímica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Priscila
P
Ferreira
i3S - Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.
Alda
A
Pereira-Henriques
Instituto de Bioquímica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Fernando L
FL
Palhano
Institute of Physiology-Instituto de Medicina Molecular, Faculty of Medicine, University of Lisbon, Lisbon, Portugal.|Department Neurosciences, Hospital de Santa Maria-CHLN, Lisbon, Portugal.
Mamede
M
de Carvalho
Instituto de Bioquímica Médica Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro, Brazil.
Debora
D
Foguel
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
David
D
Reverter
i3S - Instituto de Investigação e Inovação em Saúde da Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.|IBMC - Instituto de Biologia Molecular e Celular, Universidade do Porto, Rua Alfredo Allen, 208, 4200 - 135 Porto, Portugal.
Maria João
MJ
Saraiva
Institut de Biotecnologia i Biomedicina and Departament de Bioquímica i Biologia Molecular, Universitat Autònoma de Barcelona, Bellaterra, Spain.
Salvador
S
Ventura
D000368:Aged; D000409:Alanine / Q000737:chemistry* / Q000378:metabolism; D019943:Amino Acid Substitution; D000686:Amyloidosis / Q000235:genetics / Q000378:metabolism; D058070:Asymptomatic Diseases; D001665:Binding Sites; D018360:Crystallography, X-Ray; D005260:Female; D015870:Gene Expression; D006801:Humans; D007532:Isoleucine / Q000737:chemistry* / Q000378:metabolism; D008958:Models, Molecular; D011228:Prealbumin / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D011485:Protein Binding; D000072756:Protein Conformation, alpha-Helical; D000072757:Protein Conformation, beta-Strand; D054730:Protein Interaction Domains and Motifs; D055503:Protein Multimerization; D055550:Protein Stability; D011994:Recombinant Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism; D013816:Thermodynamics; D014633:Valine / Q000737:chemistry* / Q000378:metabolism
D011228:Prealbumin; D011994:Recombinant Proteins; D007532:Isoleucine; D014633:Valine; D000409:Alanine