Assembly inactive

Individual monomeric building blocks interconvert between assembly-inactive and assembly-active conformational states ... 

Iron Sulfur Compounds. Many molecular compounds (18—20) are known in which iron is tetrahedraHy coordinated by a combination of thiolate and sulfide donors. Of the 10 or more stmcturaHy characterized classes of Fe—S compounds, the four shown in Figure 1 are known to occur in proteins. The mononuclear iron site REPLACE occurs in the one-iron bacterial electron-transfer protein mbredoxin. The [2Fe—2S] (10) and [4Fe—4S] (12) cubane stmctures are found in the 2-, 4-, and 8-iron ferredoxins, which are also electron-transfer proteins. The [3Fe—4S] voided cubane stmcture (11) has been found in some ferredoxins and in the inactive form of aconitase, the enzyme which catalyzes the stereospecific hydration—rehydration of citrate to isocitrate in the Krebs cycle. In addition, enzymes are known that contain either other types of iron sulfur clusters or iron sulfur clusters that include other metals. Examples include nitrogenase, which reduces N2 to NH at a MoFe Sg homocitrate cluster carbon monoxide dehydrogenase, which assembles acetyl-coenzyme A (acetyl-CoA) at a FeNiS site and hydrogenases, which catalyze the reversible reduction of protons to hydrogen gas. 

The two domains of the kinase in the inactive state are held in a closed conformation by assembly of the regulatory domains... 

Enzyme activity ascribed to corepressors, which is the removal of acetyl groups from lysine residues of histone tails. Thereby the assembly of nucleosomes is maintained, which leads to a dense, transcriptional inactive chromatin structure. 

Phosphodiesterase (PDE) is one of enzymes that sue modulated in activity by binding the Ca2+-bound state of CaM. The enzyme remains inactive in a Ca2+-free assembly. Our effort has been focused on synthesizing a protein hybrid of CaM and PDE which retains its information processing function in... 

Proteasome jS-subunits are synthesized with N-terminal extensions and are inactive because a free N-terminal threonine is required for peptide-bond hydrolysis [130]. The precursor jS-subunits assemble with a-subunits to form half proteasomes com-... 

Rhodes D, Klug A (1981) Sequence-dependent helical periodicity of DNA. Nature 292 378-380 Roussel P, Andre C, Comai L, Hernandez-Verdun D (1996) The rDNA transcription machinery is assembled during mitosis in active NORs and absent in inactive NORs. J Cell Biol 133 235-246... 

These data also clearly establish that reactions of C-20 alkyl derivatives of deoxydesethyl VBL with soluble MTP or with its polymerized form as microtubules are dissociable events. Whereas the dimethyl- (6) and propyl- (10) substituted compounds inhibited the assembly of microtubules with an IC50 of about 3 x 10 M, they were inactive with steady-state microtubules at 10" M. 

Proteolytically active P-type subunits are synthesized in an inactive precursor form containing N-terminal extensions of variable lengths, the propeptides, which must be removed posttranslationally to allow the formation of active sites. This process is tied in with the assembly of the 20S proteasome in such a manner, that activation is delayed until assembly is complete and the active sites are sequestered from the cellular environment. Cleavage of the propeptide proceeds autocatalytically, reljdng on the active-site threonine, and the invariant glycine at position -1 appears to be the prime determinant of the cleavage site (Schmidtke et al. 1996 Seemiiller et al. 1996 Chen and Hochstrasser 1996). 

In the absence of steroid hormones the receptors remain in an inactive complex, designated the apo-receptor complex (review Pratt, 1993 Bohen, 1995). In the apore-ceptor complex the receptor is boimd to proteins belonging to the chaperone class. Chaperones are proteins whose levels are increased as a result of a stress situation, such as a rise in ambient temperature. The chaperones assume a central function in the folding process of proteins in the cell. Chaperones aid proteins in avoiding incorrectly folded states. They participate in the folding of proteins during and after ribosomal protein biosynthesis, during membrane transport of proteins, as well as in the correct assembly of protein complexes. 

Proteolytic processing of inactive proca-spases by autoproteolysis or by other caspases includes cleavage at two caspase consensus sites (AspX). The N-terminal pro-domain is discarded and the other two fragments assemble into the active caspase which is a tetramer with two active sites. 

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