N‐Terminal Amino Acid Sequence of Amyloid Fibril Protein AR, Prototype of a New λ‐Variable Subgroup, VλV

An amyloid fibril protein AR has been further characterized as to amino acid sequence of the first 45 N‐terminal residues. There are clear homologies with light chain‐variable regions, particularly with λ light chains and mostly with the VλII subgroup. However, there is as much as a 55% difference from the Vλ.II subgroup and even greater differences from other subgroups. This is much more than the variation known to occur within a given light chain‐variable subgroup and also a greater difference than those known to occur between the existing subgroups. For this reason protein AR appears to be the prototype for a new variable subgroup of λ chains. In agreement with the National Biomedical Research Foundation, this new subgroup is termed VλV.