Analysis of amyloid fibrils in the cheetah (Acinonyx jubatus)

Abstract

Recently, a high prevalence of amyloid A (AA) amyloidosis has been documented among captive cheetahs worldwide. Biochemical analysis of amyloid fibrils extracted from the liver of a Japanese captive cheetah unequivocally showed that protein AA was the main fibril constituent. Further characterization of the AA fibril components by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS–PAGE) and Western blot analysis revealed three main protein AA bands with approximate molecular weights of 8, 10 and 12 kDa. Mass spectrometry analysis of the 12-kDa component observed in SDS–PAGE and Western blotting confirmed the molecular weight of a 12,381-Da peak. Our finding of a 12-kDa protein AA component provides evidence that the cheetah SAA sequence is longer than the previously reported 90 amino acid residues (∼10 kDa), and hence SAA is part of the amyloid fibril.

Keywords:

• Amyloid
• serum amyloid A (SAA)
• amyloid A protein (AA)
• cheetah

Abbreviations
AA	=	amyloid A
SAA	=	serum amyloid A
SDS–PAGE	=	sodium dodecyl sulphate–polyacrylamide gel electrophoresis
MALDI/TOF–MS	=	matrix-assisted laser desorption-ionization/time-of-flight–mass spectrometry

Abbreviations
AA	=	amyloid A
SAA	=	serum amyloid A
SDS–PAGE	=	sodium dodecyl sulphate–polyacrylamide gel electrophoresis
MALDI/TOF–MS	=	matrix-assisted laser desorption-ionization/time-of-flight–mass spectrometry