scholarly journals The Gag-Pol Encoded Proteinase of an Avian Retrovirus Expressed in E. coli Can Produce a Novel Proteinase (PR+IIeGly) That Is Two Amino Acids Larger at Its Carboxy-Terminal Region Than the Major Gag Proteinase (PR)

Virology ◽  
1995 ◽  
Vol 207 (1) ◽  
pp. 185-190
Author(s):  
Jiřı́ Brynda ◽  
Milan Fábry ◽  
Magda Hořejšı́ ◽  
Juraj Sedláček
Keyword(s):  
Amino Acids ◽  
Terminal Region ◽  
E Coli ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal

The Carboxy-Terminal Region of Sturgeon Muscle Aldolase

1971 ◽  
Vol 49 (3) ◽  
pp. 372-375
Author(s):  
P. J. Anderson
Keyword(s):  
Amino Acids ◽  
Terminal Region ◽  
Rabbit Muscle ◽  
Muscle Enzyme ◽  
Molar Ratios ◽  
Carboxy Terminal Region ◽  
Kinetic Effects ◽  
Carboxy Terminal ◽  
Similar Kinetic

The modification of the carboxy-terminal of sturgeon muscle aldolase with carboxypeptidase produces similar kinetic effects to those observed on modification of the rabbit muscle enzyme. The nature and molar ratios of amino acids released indicate that differences between the two enzymes occur in the carboxy-terminal region.

scholarly journals Identification of Protein Instability Determinants in the Carboxy-Terminal Region of c-Myb Removed as a Result of Retroviral Integration in Murine Monocytic Leukemias

1999 ◽  
Vol 73 (3) ◽  
pp. 2038-2044 ◽  
Author(s):  
Juraj Bies ◽  
Viktor Nazarov ◽  
Linda Wolff
Keyword(s):  
Amino Acids ◽  
Insertional Mutagenesis ◽  
Leucine Zipper ◽  
Premature Termination ◽  
Terminal Region ◽  
26S Proteasome ◽  
Proviral Integration ◽  
Carboxy Terminal Region ◽  
Myb Protein ◽  
Carboxy Terminal

ABSTRACT The c-myb oncogene has been a target of retroviral insertional mutagenesis in murine monocytic leukemias. One mechanism by which c-myb can be activated is through the integration of a retroviral provirus into the central portion of the locus, causing premature termination of c-myb transcription and translation. We had previously shown that a leukemia-specific c-Myb protein, truncated at the site of proviral integration by 248 amino acids, had approximately a fourfold-increased half-life compared to the normal c-Myb protein, due to its ability to escape rapid degradation by the ubiquitin-26S proteasome pathway. Here we provide evidence for the existence of more than one instability determinant in the carboxy-terminal region of the wild-type protein, which appear to act independently of each other. The data were derived from examination of premature termination mutants and deletion mutants of the normal protein, as well as analysis of another carboxy-terminally truncated protein expressed in leukemia. Evidence is provided that one instability determinant is located in the terminal 87 amino acids of the protein and another is located in the vicinity of the internal region that has leucine zipper homology. In leukemias, different degrees of protein stability are attained following proviral integration depending upon how many determinants are removed. Interestingly, although PEST sequences (rich in proline, glutamine, serine, and threonine), often associated with degradation, are found in c-Myb, deletion of PEST-containing regions had no effect on protein turnover. This study provides further insight into how inappropriate expression of c-Myb may contribute to leukemogenesis. In addition, it will facilitate further studies aimed at characterizing the specific role of individual regions of the normal protein in targeting to the 26S proteasome.

scholarly journals The Oncoprotein Tax Binds the SRC-1-Interacting Domain of CBP/p300 To Mediate Transcriptional Activation

2001 ◽  
Vol 21 (16) ◽  
pp. 5520-5530 ◽  
Author(s):  
Kirsten E. S. Scoggin ◽  
Aida Ulloa ◽  
Jennifer K. Nyborg
Keyword(s):  
Amino Acids ◽  
Transcriptional Activation ◽  
Molecular Mechanisms ◽  
Single Point ◽  
Terminal Region ◽  
Transactivation Domain ◽  
Human T Cell ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal ◽  
Interacting Domain

ABSTRACT Oncogenesis associated with human T-cell leukemia virus (HTLV) infection is directly linked to the virally encoded transcription factor Tax. To activate HTLV-1 transcription Tax interacts with the cellular protein CREB and the pleiotropic coactivators CBP and p300. While extensively studied, the molecular mechanisms of Tax transcription function and coactivator utilization are not fully understood. Previous studies have focused on Tax binding to the KIX domain of CBP, as this was believed to be the key step in recruiting the coactivator to the HTLV-1 promoter. In this study, we identify a carboxy-terminal region of CBP (and p300) that strongly interacts with Tax and mediates Tax transcription function. Through deletion mutagenesis, we identify amino acids 2003 to 2212 of CBP, which we call carboxy-terminal region 2 (CR2), as the minimal region for Tax interaction. Interestingly, this domain corresponds to the steroid receptor coactivator 1 (SRC-1)-interacting domain of CBP. We show that a double point mutant targeted to one of the putative α-helical motifs in this domain significantly compromises the interaction with Tax. We also characterize the region of Tax responsible for interaction with CR2 and show that the previously identified transactivation domain of Tax (amino acids 312 to 319) participates in CR2 binding. This region of Tax corresponds to a consensus amphipathic helix, and single point mutations targeted to amino acids on the face of this helix abolish interaction with CR2 and dramatically reduce Tax transcription function. Finally, we demonstrate that Tax and SRC-1 bind to CR2 in a mutually exclusive fashion. Together, these studies identify a novel Tax-interacting site on CBP/p300 and extend our understanding of the molecular mechanism of Tax transactivation.

scholarly journals The Carboxy-Terminal Region of apoA-I Is Required for the ABCA1-Dependent Formation of α-HDL But Not Preβ-HDL Particles in Vivo†

Biochemistry ◽  
2007 ◽  
Vol 46 (19) ◽  
pp. 5697-5708 ◽  
Author(s):  
Angeliki Chroni ◽  
Georgios Koukos ◽  
Adelina Duka ◽  
Vassilis I. Zannis
Keyword(s):  
Terminal Region ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal

Tubulin folding is altered by mutations in a putative GTP binding motif

1996 ◽  
Vol 109 (6) ◽  
pp. 1471-1478 ◽  
Author(s):  
J.C. Zabala ◽  
A. Fontalba ◽  
J. Avila
Keyword(s):  
Intramolecular Interaction ◽  
Terminal Region ◽  
Binding Motif ◽  
Beta Tubulin ◽  
Alpha Tubulin ◽  
Proposed Model ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal ◽  
Hydrolysis Of

Tubulins contain a glycine-rich loop, that has been implicated in microtubule dynamics by means of an intramolecular interaction with the carboxy-terminal region. As a further extension of the analysis of the role of the carboxy-terminal region in tubulin folding we have mutated the glycine-rich loop of tubulin subunits. An alpha-tubulin point mutant with a T150-->G substitution (the corresponding residue present in beta-tubulin) was able to incorporate into dimers and microtubules. On the other hand, four beta-tubulin point mutants, including the G148-->T substitution, did not incorporate into dimers, did not release monomers, but were able to form C900 and C300 complexes (intermediates in the process of tubulin folding). Three other mutants within this region (which approximately encompasses residues 137–152) were incapable of forming dimers and C300 complexes but gave rise to the formation of C900 complexes. These results suggest that tubulin goes through two sequential folding states during the folding process, first in association with TCP1-complexes (C900) prior to the transfer to C300 complexes. It is this second step that implies binding/hydrolysis of GTP, reinforcing our previous proposed model for tubulin folding and assembly.

scholarly journals THE DISTRIBUTION OF ANTIGENIC DETERMINANTS IN RAT SKIN COLLAGEN

1971 ◽  
Vol 133 (6) ◽  
pp. 1309-1324 ◽  
Author(s):  
Herbert Lindsley ◽  
Mart Mannik ◽  
Paul Bornstein
Keyword(s):  
Terminal Region ◽  
Antigenic Determinants ◽  
Collagen Molecule ◽  
Rat Skin ◽  
Amino Terminal ◽  
Skin Collagen ◽  
Native Collagen ◽  
Carboxy Terminal Region ◽  
Carboxy Terminal ◽  
Hyperimmune Rabbit

Immunological studies of rat skin collagen were carried out with a sensitive and quantitative radioimmunoassay. Hyperimmune rabbit antisera to rat skin collagen and isolated α2 chains were used. Iodine-labeled α chains and CNBr-produced peptides served as test antigens, and native collagen, α chains, and CNBr peptides were employed as inhibitors in the assay. The α1 and α2 chains were immunologically distinct. Although the α1 chain was not immunogenic, antibodies to α1 were detected in antisera to the intact collagen molecule. The major antigenic determinant of the α1 chain was located in α1-CB6 which constitutes the carboxy-terminal region of the chain. The α2 chain contained two non-cross-reacting antigenic determinants, one in the amino-terminal region (α2-CB1) and the other in the carboxy-terminal region (α2-CB5) of the chain. The native collagen molecule was less effective than isolated α chains in inhibiting binding of labeled peptides to antisera, indicating that antigenic determinants were less accessible in the triple helical molecule. These immunologic studies are consistent with preliminary comparative biochemical data which indicate that interspecies structural differences in collagen predominate at both the amino- and carboxy-terminal ends of the chains.

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