BACKGROUND: The seven-residue heptad repeat is the accepted hallmark of coiled coils. In extended filamentous proteins, however, contiguous patterns of heptads are often disrupted by 'skips' and 'stammers'. The structural consequences and roles of these digressions are not understood. RESULTS: In a cytoskeleton protein from Giardia lamblia, heptads flank eleven-residue units (hendecads) to give a 7-11-7 motif that dominates the sequence. Synthetic peptides made to the consensus sequence of this motif fold in solution to fully helical, parallel dimers. Both the sequence pattern and these experimental data are consistent with the coiled-coil model. We note that breaks in other extended coiled coils can also be reconciled by hendecad insertions. CONCLUSIONS: The heptad paradigm for the coiled coil must be expanded to include hendecads. As different combinations of heptads and hendecads will give different overall sequence motifs, we propose that these provide a mechanism to promote cognate protein pairings during the folding of extended coiled coils in the cell.
BACKGROUND: The seven-residue heptad repeat is the accepted hallmark of coiled coils. In extended filamentous proteins, however, contiguous patterns of heptads are often disrupted by 'skips' and 'stammers'. The structural consequences and roles of these digressions are not understood. RESULTS: In a cytoskeleton protein from Giardia lamblia, heptads flank eleven-residue units (hendecads) to give a 7-11-7 motif that dominates the sequence. Synthetic peptides made to the consensus sequence of this motif fold in solution to fully helical, parallel dimers. Both the sequence pattern and these experimental data are consistent with the coiled-coil model. We note that breaks in other extended coiled coils can also be reconciled by hendecad insertions. CONCLUSIONS: The heptad paradigm for the coiled coil must be expanded to include hendecads. As different combinations of heptads and hendecads will give different overall sequence motifs, we propose that these provide a mechanism to promote cognate protein pairings during the folding of extended coiled coils in the cell.
Authors: Xingcheng Lin; Jeffrey K Noel; Qinghua Wang; Jianpeng Ma; José N Onuchic Journal: Proc Natl Acad Sci U S A Date: 2018-07-16 Impact factor: 11.205
Authors: Richard Y-C Huang; Stanley R Krystek; Nathan Felix; Robert F Graziano; Mohan Srinivasan; Achal Pashine; Guodong Chen Journal: MAbs Date: 2017-11-14 Impact factor: 5.857
Authors: Dale F Kreitler; Zhihui Yao; Jay D Steinkruger; David E Mortenson; Lijun Huang; Ritesh Mittal; Benjamin R Travis; Katrina T Forest; Samuel H Gellman Journal: J Am Chem Soc Date: 2019-01-15 Impact factor: 15.419