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Primary structure of diphtheria toxin fragment B: structural similarities with lipid-binding domains

Two different lipid-associating domains have been identified in the B fragment of diphtheria toxin using automated Edman degradation of its cyanogen bromide peptides, secondary structure prediction analysis, and comparisons with known phospholipid-interacting proteins. The first domain is located in...

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Detalles Bibliográficos
Formato: Texto
Lenguaje:English
Publicado: The Rockefeller University Press 1980
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2110781/
https://www.ncbi.nlm.nih.gov/pubmed/7462325
Descripción
Sumario:Two different lipid-associating domains have been identified in the B fragment of diphtheria toxin using automated Edman degradation of its cyanogen bromide peptides, secondary structure prediction analysis, and comparisons with known phospholipid-interacting proteins. The first domain is located in the highly hydrophilic (polarity index [PI] = 61.0%) 9.00-dalton N-terminal region of fragment B. This region shows primary and predicted secondary structures dramatically similar to those found for the phospholipid headgroup-binding domains of human apolipoprotein A1 (surface lipid-associating domain). The second domain is located in the highly hydrophobic (PI = 32.4%) middle region of fragment B. Its structure resembles that found for the membranous domain of intrinsic membrane proteins (transverse lipid-associating domain). In contrast, the hydrophilic C-terminal 8,000-dalton region of fragment B (PI = 53.8%) does not show structural similarity with lipid- associating domains.