N-terminal regions

The helices at the N-terminal regions of the two polypeptide chains are intertwined and make extensive contacts in the central part of the molecule to form a stable core. This core supports two "heads", each comprising the last three helices from one polypeptide chain. Alpha helix 3 in the middle of the subunit chain is quite long and forms the main link between the core and the head. 

Figure 8.19 The a helices of the N-terminal region of the trp repressor are involved in subunit interactions and form a stable core in the middle of the dimer. Alpha helices 4-6, which include the helix-turn-helix motif, form two "head" regions at the two ends of the molecule. Alpha helix 3 connects the core to the head in both subunits. (Adapted from R.W. Schevitz et al., Nature 317 782-786, 1985.)...

TBP mutants lacking the N-terminal region are fully functional in promoter binding and stimulation of basal transcription and therefore these two functions must be provided by the C-terminal domain. Furthermore, the C-terminal domain of yeast TBP contains all the functions essential for normal yeast cell growth and for responses to specific transcriptional activators with a net negative charge. This C-terminal domain contains two homologous... 

Figure 11.13 Schematic diagram of the three-dimensional structure of subtilisin viewed down the central parallel p sheet. The N-terminal region that contains the a/p stmcture is blue.

Both the a and the y subunits of G proteins are anchored to the membrane by lipids covalently bound to the N-terminal region of the Ga chain... 

Histone tails are the N-terminal regions of histones which reach outside the nucleosomes. They are not essential for the formation in of nucleosomes but are required for the formation of higher-order chromatin structures. The histone tails are also known to be heavily posttranslationally modified by acetylation, phosphorylation, methylation, etc. and are important for the regulation of gene activity. 

The nonstructural region of the precursor, harboring the viral replication machinery, is cut into its mature components in a maturation reaction in which two viral proteases (NS2-pro and NS3/4A-pro) cooperate. Site-directed mutagenesis of an other wise infectious cDNA has shown that both HCV-encoded proteases are necessary for viral infectivity, but most of the attention has so far been focused on one of them a member of the serine protease family (EC 3.4.21) located in the N-terminal region of the viral NS3 protein. 

In another investigation, ELP[V5L2G3-90] with three lysines in the N-terminal region was immobihzed on a glass surface in a microreactor to enable temperature-controlled positioning of ELP fusion proteins. For this purpose, the glass surface was first functionalized with A -2-(aminoethyl)-3-aminopropyltrimethoxysilane, followed by glutaraldehyde treatment and reductive amination to immobilize the biopolymer on the surface (Fig. 17b) [132]. 

The four hypervariable regions are indicated by the bars. The constant regions in this disanalog family include a 50 AA N-terminal region (not shown) and the 6 cysteine residues. 

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