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Core, catalytic

Zhang, G., Ruoho, A.E., Hurley, J.H. Structure of the adenylyl cyclase catalytic core. Nature 386 247-253, 1997. [Pg.281]

The SCF, a ubiquitin ligase complex, consists of the piimaiy subunits Skpl, Cullin and Rbx/Rocl. While the Rbx/Cul components form the E3 ligase catalytic core... [Pg.1133]

All RTKs contain between one and three tyrosines in the kinase activation loop, which is composed of subdomains VII and VIII of the protein kinase catalytic core. Phosphorylation of these tyrosines has been shown to be critical for stimulation of catalytic activity and biological function for a number of RTKs, including insulin receptor, FGF receptor, VEGF receptor, PDGF receptor, Met (hepatocyte growth factor receptor), and TrkA (NGF receptor). A major exception is the EGF receptor, for which autophosphorylation of a conserved tyrosine in the activation loop does not seem to be involved in signaling. Substitution of tyrosine with phenylalanine has no effect on RTK activity or downstream signals. [Pg.136]

Despite the similar functions of each isozyme, only two regions of amino acid homology exist (X and Y), one of 150 and a second of 120 amino acid residues, which are 54% and 42% identical among the isozymes but are differentially localized within each enzyme (Fig. 20-3). The X and Y domains form the catalytic core of the enzyme. A characteristic of the (3 and 8 isoforms is that relatively few amino acids (40-110) separate the X and Y entities, whereas a much larger separation is observed for the PLCy isoform (approx. 400). In addition, in PLCy, the region between X and Y contains amino acid sequences that are found in nonreceptor tyrosine kinases (SH2 and SH3 domains). All four isoforms possess pleckstrin homology (PH) domains. The latter are considered to enable the enzyme to become tethered to the plasmalemma via an interaction with PI(4,5)P2. In addition, all PLC isoforms possess an E-F hand domain, which is located between PH and X domains, and a C2 domain, which is located close to the Y domain. [Pg.351]

The first class of DUBs discovered, the ubiquitin C-terminal Aydrolases (UCHs), is a relatively small class vith only four members in humans and one in budding yeast. UCHs are cysteine proteases related to the papain family of cysteine proteases. Most UCHs consist entirely of a catalytic core that has a molecular mass of about 25 kDa, although Bapl and UCH37 have C-terminal extensions [21, 22], All UCHs have a highly conserved catalytic triad consisting of the active-site cysteine, histidine, and aspartate residues that are absolutely required for function [23]. [Pg.194]

The ubiquitin specific processing proteases (referred to as UBPs in yeast and USPs in human and mouse) were the second class of DUBs discovered. Catalytically, the UBPs are very similar to the UCHs in that they also utilize the catalytic triad of an active-site cysteine and a conserved histidine and aspartate. The UBP catalytic core... [Pg.195]

The catalytic core of the proteasome is a threonine protease. Based on the crystal structure of the proteasome, it was concluded that proteasome functions through a new kind of proteolytic mechanism. In... [Pg.711]

The catalytic core is the part that ultimately cleaves the ubiquitinated protein into small peptides anywhere from 3 amino acids to 32 amino acids long. The peptides generated are probably further hydrolyzed to generate free amino acids by other proteases and amino peptidases. The proteases that break down the products of the proteasome action include but not limited to Thimet oligo peptidase, tricorn protease, and tripeptidyl protease... [Pg.712]

The 19S RC recognizes the polyubiquitinated substrate and channels the substrate into the catalytic 2 OS core of the proteasome. It also has the capacity to regulate the activity of the catalytic core and determine the nature of the degradation process. Usually one 19S RC is attached to either end of the catalytic core. The subunits of the 19S RC are highly conserved across evolution. ° ° Two subcomplexes can be recognized within the 19S RC called the base and the lid (Figure 6(a)). [Pg.712]

Another level of specificity of DUBs is with respect to the substrates that are deubiquitinated. Although not much is known about how DUBs choose their targets, domains outside the catalytic core might play a role in determining the substrate to which a given DUB binds. For example, a CAP-Gly domain (a conserved glycine-rich domain found in some cytoskeleton-associated proteins (CAPs)) of CYLD functions in its interaction with NF-kB essential modulator (NEMO), a putative CYLD substrate. [Pg.718]

SUMO attachment can be removed by SUMO-specific isopeptidases just as UCHs and UBPs remove ubiquitin from substrate proteins. Thus, sumoylation is also a reversible modification. SUMO-specific isopeptidases possess a Cys residue in their catalytic core similar to UCHs and UBPs. Two SUMO-specific isopeptidases in yeast are called Ulpl and Ulp2. In humans, six Ulp homologues have been identified and are given the name sentrin-specific proteases (SENPs) because SUMO was previously known as sentrin . [Pg.732]

Tlie two proposed metal binding sites were (1) the ribozyme P9/G10.1 site, located at the junction between stem (helix) II and the conserved catalytic core, and (2) the substrate Pl.l, scissile phosphate, site (see Figure 6.18). [Pg.280]

APP is endoproteolytically processed by BACEl and y-secretase to release ABPl-40 and ABPl-42, which aggregate to form senile plaques in AD brains. The C-terminus of ABP, C99, is generated by y-secretase, which has activity that is dependent on PSl or PS2. It has been suggested that PS proteins are the catalytic core of the proteolytic activity of the complex, but a number of other proteins mandatory for y-secretase cleavage have also been discovered. The exact role of PS in the y-secretase activity remains a matter of debate because cells devoid of PS still produce some forms of ABP. [Pg.243]

Fig. 2. The P4-P6-domain of the group I intron of Tetrahymena thermophila. A Schematic representation of the secondary structure of the whole self-cleaving intron (modified after Cate et al. [34]). The labels for the paired regions P4 to P6 are indicated. The grey shaded region indicate the phylogenetically conserved catalytic core. The portion of the ribozyme that was crystallized is framed. B Three dimensional structure of the P4-P6 domain. Helices of the PSabc extension are packed against helices of the conserved core due to a bend of approximately 150° at one end of the molecule... Fig. 2. The P4-P6-domain of the group I intron of Tetrahymena thermophila. A Schematic representation of the secondary structure of the whole self-cleaving intron (modified after Cate et al. [34]). The labels for the paired regions P4 to P6 are indicated. The grey shaded region indicate the phylogenetically conserved catalytic core. The portion of the ribozyme that was crystallized is framed. B Three dimensional structure of the P4-P6 domain. Helices of the PSabc extension are packed against helices of the conserved core due to a bend of approximately 150° at one end of the molecule...

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See also in sourсe #XX -- [ Pg.170 ]




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