A single amino acid can switch the oligomerization state of the alpha-helical coiled-coil domain of cartilage matrix protein.
We have studied the oligomerization of an alpha-helical coiled-coil using as an example a peptide corresponding to the C-terminal domain of cartilage matrix protein. By replacing one arginine residue, which forms an interchain ionic interaction with a glutamic acid residue, with glutamine, we found that this peptide assembles into a homotetramer at neutral pH in contrast to the native molecule which forms homotrimers. At acidic and basic pH, however, we again observed the trimer conformation. Another arginine, which is probably involved in an intrachain salt bridge, has no effect on the assembly. Our data demonstrate that besides the specific distribution of hydrophobic residues, interchain ionic interactions can be crucial in modulating the association behavior of alpha-helical coiled-coil domains.
Beck
K
K
Shriners Hospital for Children, Research Unit, Portland, OR 97201, USA. BECKKO@UMDNJ.EDU
Gambee
J E
JE
Kamawal
A
A
Bächinger
H P
HP
D000595:Amino Acid Sequence; D000818:Animals; D001120:Arginine / Q000737:chemistry*; D002356:Cartilage; D064236:Cartilage Oligomeric Matrix Protein; D002645:Chickens; D016326:Extracellular Matrix Proteins; D018698:Glutamic Acid / Q000737:chemistry; D005973:Glutamine / Q000737:chemistry; D006023:Glycoproteins / Q000737:chemistry* / Q000378:metabolism; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007477:Ions; D064235:Matrilin Proteins; D051379:Mice; D008969:Molecular Sequence Data; D017510:Protein Folding; D017433:Protein Structure, Secondary
D064236:Cartilage Oligomeric Matrix Protein; D016326:Extracellular Matrix Proteins; D006023:Glycoproteins; D007477:Ions; C577540:Matn1 protein, mouse; D064235:Matrilin Proteins; C577553:TSP5 protein, human; D005973:Glutamine; D018698:Glutamic Acid; D001120:Arginine