Mutations of the WD repeats that compromise Tup1 repression function maintain structural integrity of the WD domain trypsin-resistant core.
The yeast global transcriptional repressor Tup1 contains 7 WD repeats in its C-terminus that form a beta-propeller-like structure, in which the first and last WD repeats interact to make a closed circle. The WD domains of all proteins tested, including Tup1, form a compact structure resistant to trypsin digestion (Garcia-Higuera et al., Biochemistry 35 (1996) 13985-13994). We found that the in vitro formation of the trypsin-resistant core of Tup1 requires just five WD repeats (WD2-6). Deletion of the ST region between WD1 and WD2 destabilizes the trypsin-resistant core, but maintains Tup1 repression function in vivo. Linker insertion and point mutations in the WD repeats that compromise Tup1 repression function in vivo still maintain the trypsin-resistant core in vitro These results indicate that structural perturbation of the WD domain structure cannot explain the effects of these mutations on Tup1 repression function.
Zhang
Zhizhou
Z
Department of Biochemistry and Molecular Biology, 3035 Arlington Avenue, Medical College of Ohio, Toledo, OH 43614, USA.
Varanasi
Usha
U
Carrico
Pauline
P
Trumbly
Robert J
RJ
D000595:Amino Acid Sequence; D001483:Base Sequence; D018900:Dinucleotide Repeats; D008958:Models, Molecular; D008969:Molecular Sequence Data; D016296:Mutagenesis; D016254:Mutagenesis, Insertional; D017433:Protein Structure, Secondary; D020449:Repetitive Sequences, Amino Acid; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D017384:Sequence Deletion; D013379:Substrate Specificity; D014357:Trypsin / Q000378:metabolism*
D012097:Repressor Proteins; D014357:Trypsin