Ribbon structures

FIGURE 6,37 Ribbon structures of several protein modules utilized in the construction of... 

FIGURE 16.17 Structure of chyinotrypsiu (white) ill a complex with egliii C (blue ribbon structure), a target protein. The residues of the catalytic triad (His ", Asp , and Ser ) are highlighted. His (blue) is flanked above by Aspios on the right by Ser (yel-... 

R. Kniep, D. Mootz and A. Rabenau, Angew. Chem. Int. Edn. Engl. 13, 403-4 (1973). More complex chain and ribbon structures are observed for the ternary compounds a-AsSel, -AsSel, a-AsTel and -AsTel, all of which are isoelectronic with Seoo and Teoo (R- Kniep and H. D. Reski, Angew. Chem. Int. Edn. Engl. 20, 212-4 (1981)). 

The general topology of rubredoxins is also observed in the general zinc-ribbon motif in RNA polymerases or in transcription factors (59). The first published zinc-ribbon structure was that of the nucleic-acid binding domain of human transcriptional elongation factor TFIIS (PDB file ITFI) 40). These zinc binding domains and rubredoxins... 

Ribbon structures of two redox proteins, cytochrome c (a) and plastocyanin (b). The blowups show the active sites where transition metal atoms are located. 

Schematic representation of carbon filaments of different structure produced by metal-catalyzed decomposition of methane, (a) Platelet structure, (b) "herringbone" structure, and (c) ribbon structure. MP denotes a nanosized metal particle.

Figure 15 (a) Ribbon structure of Ph3PS(I2) 3 and (b) stepped layers of Ph3PS(I2) 3... 

Figure 5.40 Electron micrographs of extended ribbon structure from DMPA (44) in 50 mM Tris-HCl buffer (pH 8.0) (a) after aging at 25°C and (b) gel of ribbons after aging at 25°C for 1 month. Bars = 0.1 p,m. Reprinted with permission from Ref. 157. Copyright 1992 by the American Chemical Society.

Fig. 6 Wave-like ribbon structure of complex 18.p-xylene.l.5(DMF), where DMF=dimethyl-formamide. Guest p-xylene occupies the cavitand molecular cavity, while disordered DMF (only one position shown) occupies the cage created by pendant arms at the lower rim [39]... 

Fig. 10 Wave-like ribbon structure of (C-methylcalix[4]resorcinarene).2(4,4 -bipyridine) (CH3CN) with C-methylcalix[4]resorcinarene in a bowl conformation [52]...

Fig. 26a,b. High resolution height SFM-micrographs of a 14-ABG-PS on mica [86] b Twisted ribbon structure of polypeptide /i-sheets [ 167]. The plectoneme conformation is caused by the backward folding of the torsionally stressed molecules [86]. Insert in (a) depicts a plectoneme supercoil... 

Figure 3. Model of (p a)s TIM barrel from triose phosphate isomerase. Numbered arrow and twisted ribbon structures are beta sheets and alpha helicies, respectively. (Adapted and reproduced from Ref. 66 with permission. Cop3night 1984 American Association for the Advancement of Science.)...

Fig. 14.1. Ribbon structure (magenta) of the phosphorylase kinase crystal structure 2PHK (20) bound with ATP (green carbons, colored by atom type) and substrate peptide (light blue ribbon). The N- and C-terminal lobes are highlighted the hinge region is shown in cyan, the a-C helix in gray, and the -loop in orange.

Stereoscopic ribbon structure of the HIV-1 protease with the synthetic inhibitor Sequinivircc bound in the active site. One of the two identical subunits (top) is shaded darker than the second (bottom). When mutated, the amino acid side chains shown in ball-and-stick form with residue numbers shown for the top subunit led to drug-resistant viruses. Courtesy of Alex Wlodawer, National Cancer Institute.01... 

Figure 15-19 Drawings of the active site of E. coli dihydrofolate reductase showing the hound ligands NADP+ and tetrahydrofolate. Several key amino acid side chains are shown in the stereoscopic views on the right. The complete ribbon structures are on the left. (A) Closed form. (B) Open form into which substrates can enter and products can escape. From Sawaya and Kraut.381 Courtesy of Joseph Kraut. Molscript drawings (Kraulis, 1991).

Figure 30-10 (A) Schematic drawing of a synapse. (B) Electron micrograph showing the synaptic junctions in the basal part (pedicle) of a retinal cone cell of a monkey.403 Each pedicle contains synaptic contacts with 12 triads, each made up of processes from a bipolar cell center that carries the principal output signal and processes from two horizontal cells that also synapse with other cones. A ribbon structure within the pedicle is characteristic of these synapses. Note the numerous synaptic vesicles in the pedicle, some arranged around the ribbon, the synaptic clefts, and the characteristic thickening of the membranes surrounding the cleft (below the ribbons). Micrograph courtesy of John Dowling.

Figure 31-7 Ribbon structures of some defensins. (A) Structure of a human fl-defensin showing the three disulfide bonds. From Bauer et al.134 Courtesy of Heinrich Sticht. (B) Comparison of the folding patterns of four types of defensins. Mammalian a- and P-defensins are all P sheets with somewhat different arrangements of disulfide bridges. Insect and plant defensins have an a helix joined to the P sheet. Mammalian and insect defensins have three disulfide bridges, while plant defensins have four. From Hoffmann et al.12 Courtesy of Jules A. Hoffmann.

Fig. 3. The ribbon structure of coil-Ser [pdb identifier, lcos (Lovejoy et al, 1993)]. The structure reveals a mixed parallel/antiparallel three-helix bundle, which is influenced by the three core tryptophan side chains, shown in space-filling representation.

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