Domain connectivity

The catalytic subunit of cAPK contains two domains connected by a peptide linker. ATP binds in a deep cleft between the two domains. Presently, crystal structures showed cAPK in three different conformations, (1) in a closed conformation in the ternary complex with ATP or other tight-binding ligands and a peptide inhibitor PKI(5-24), (2) in an intermediate conformation in the binary complex with adenosine, and (3) in an open conformation in the binary complex of mammalian cAPK with PKI(5-24). Fig.l shows a superposition of the three protein kinase configurations to visualize the type of conformational movement. 

FIGURE 17.30 (a) A ribbon diagram and (b) a molecular graphic showing two slightly different views of the structure of troponin C. Note the long a-helical domain connecting the N-terminal and C-terminal lobes of the molecule. 

Centrins are calmodulin-like proteins that have an important function in the organization and duplication of microtubules. Like CaM, centrin is also comprized of two structurally independent globular domains connected by a flexible tether, and each domain is... 

Figure 5.45. PEEM image of the Pt/YSZ microstructure showing three circular YSZ domains connected via channels which are surrounded by a Pt film. Inside the window marked from 1-3 the digitized PEEM intensity has been integrated for the measurements displayed in Fig. 5.46.28 Reprinted with permission from Wiley-VCH.

The Terrestrial Component. These papers illustrate the application of temporal, spatial, and domain connectivity. Chemicals associated with people, food eaten by people, insects, and other organisms that compete with people for food, and other biomass must be identified. Since most of these chemical groups are terrestrial, spatial boundaries such as urban, biome, regional, and global are used. From a system perspective, these boundaries exclude water and air and require that they be placed in the "rest of the system" category. This type of boundary introduces the assumption that food, competitors for food, or any chemical that is discharged to or harvested from the air or water is ignored or assumed to be external to the system studied. 

Euler characteristic and the minority domain volume fraction. Because the Euler characteristic is the direct measure of the domain connectivity, we identify the domain percolation at the point where the Euler characteristic attains zero value. 

IGF-1 and -2 display identical amino acid residues at 45 positions, and exhibit in excess of 60% sequence homology. Both display A and B domains, connected by a short C domain — similar to proinsulin. However, unlike in the case of proinsulin, the IGF s C domain is not subsequently removed. The predicted tertiary structure of both IGFs closely resemble that of proinsulin. The overall amino acid homology displayed between insulin and the two IGFs is in excess of 40%. 

It is not easy to mimic the shuffling of domains in vitro by manipulation of genes. For example, each catalytic polypeptide chain of the multimeric E. coli aspartate transcarbamoylase (ATCase) is composed of two globular domains connected by two interdomain helixes. The E. coli enzyme ornithine transcarbamoylase (OTCase) is 32% identical in sequence and thus of presumably similar structure (see section D8). None of the chimeras in which a domain from one enzyme was attached to the corresponding partner in the other is active. The specific intrachain and interchain side-chain interactions also have to evolve for the Correcting packing.32... 

Structural analyses have revealed a typical architecture of the S100 proteins. Each S100 protein is composed of two EF-hand Ca2+-binding domains connected by a central hinge region (Fritz and Heizmann, 2004 Bhattacharya et al., 2004 ... 

Rg. 4.2 The monomeric enzyme consists of a smaller N-termlnal and a larger C-terminal domain, connected by a linker peptide. The catalytic site to which ATP binds is deeply embedded between the interface of the two domains. 

Vaz WLC, Melo ECC, Thompson TE. Translational diffusion 47. and fluid domain connectivity in a two-component, two-phase phospholipid bilayer. Biophys. J. 1989 56 869-875. 

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