Once the parasite enters a host erythrocyte, the cell undergoes a series of important modifications, one of which is the insertion of parasite proteins into the erythrocyte membrane to form knob-like structures.
A smooth surface in the P. chabaudi-infected erythrocytes was quite obvious in comparison with P. falciparum-infected erythrocytes, which form knob-like structures on the erythrocyte surface [ 44– 47], unlike the very smooth surface topography of uninfected human erythrocytes observed in the scanning electron) and transmission electron) micrographs.
Hence, most of the NORs have only part of their rRNA gene arrays being transcribed at any particular time, while the remaining arrays adopt a heterochromatic configuration forming knobs at perinucleolar location [9], [11].
The three A subunits appear to have regions of their density protruding away from the center of the A3B3 complex forming knob-like densities that are thought to be representative of an amino acid insertion near the amino-termini [21].
Mutation of a single Trp residue that forms knob-in-hole interactions across the dimer dimer interface abrogates hexamer formation, suggesting that this residue is the center of a protein protein association hot spot.
We focused on two residues that form a "knob" and a "hole" pair, G74 and T76, since steric complementarity plays an important role at these positions.
The authors instead suggested that the wing bones contained metaplastic tissue able to form the knob.
The entire TPR domain (residues 26 131) consists of three pairs of TPR repeats where each TPR consists of two antiparallel α-helices separated by a turn, such that apposed bulky and small side chains form a "knob and hole" structure.
The tail club (Fig. 1) of ankylosaurid dinosaurs is composed of tightly interlocking distal caudal vertebrae, forming the handle, and large terminal osteoderms, forming the knob [1].
Tail clubs are composed of both the handle vertebrae and the large terminal osteoderms that surround and partially enclose the distalmost vertebrae, forming the knob (Fig. 1).
For example, in maize, tandem repeats form chromosomal knobs that reduce recombination rate in adjacent regions (see Ghaffari et al. 2013).
