scholarly journals The cytosolic carboxypeptidases CCP2 and CCP3 catalyze posttranslational removal of acidic amino acids

2014 ◽  
Vol 25 (19) ◽  
pp. 3017-3027 ◽  
Author(s):  
Olivia Tort ◽  
Sebastián Tanco ◽  
Cecilia Rocha ◽  
Ivan Bièche ◽  
Cecilia Seixas ◽  
...  
Keyword(s):  
Amino Acids ◽  
Posttranslational Modification ◽  
Protein Modification ◽  
Functional Characterization ◽  
Protein Family ◽  
Terminal Protein ◽  
Microtubule Cytoskeleton ◽  
Acidic Amino Acids ◽  
Carboxy Terminal

The posttranslational modification of carboxy-terminal tails of tubulin plays an important role in the regulation of the microtubule cytoskeleton. Enzymes responsible for deglutamylating tubulin have been discovered within a novel family of mammalian cytosolic carboxypeptidases. The discovery of these enzymes also revealed the existence of a range of other substrates that are enzymatically deglutamylated. Only four of six mammalian cytosolic carboxypeptidases had been enzymatically characterized. Here we complete the functional characterization of this protein family by demonstrating that CCP2 and CCP3 are deglutamylases, with CCP3 being able to hydrolyze aspartic acids with similar efficiency. Deaspartylation is a novel posttranslational modification that could, in conjunction with deglutamylation, broaden the range of potential substrates that undergo carboxy-terminal processing. In addition, we show that CCP2 and CCP3 are highly regulated proteins confined to ciliated tissues. The characterization of two novel enzymes for carboxy-terminal protein modification provides novel insights into the broadness of this barely studied process.

scholarly journals Human xylosyltransferase I and N-terminal truncated forms: functional characterization of the core enzyme

2006 ◽  
Vol 394 (1) ◽  
pp. 163-171 ◽  
Author(s):  
Sandra Müller ◽  
Jennifer Disse ◽  
Manuela Schöttler ◽  
Sylvia Schön ◽  
Christian Prante ◽  
...  
Keyword(s):  
Amino Acids ◽  
Catalytic Activity ◽  
Binding Capacity ◽  
Functional Characterization ◽  
Terminal Region ◽  
Binding Motif ◽  
Heparin Binding ◽  
Loss Of Function ◽  
The Impact

Human XT-I (xylosyltransferase I; EC 2.4.2.26) initiates the biosynthesis of the glycosaminoglycan linkage region and is a diagnostic marker of an enhanced proteoglycan biosynthesis. In the present study, we have investigated mutant enzymes of human XT-I and assessed the impact of the N-terminal region on the enzymatic activity. Soluble mutant enzymes of human XT-I with deletions at the N-terminal domain were expressed in insect cells and analysed for catalytic activity. As many as 260 amino acids could be truncated at the N-terminal region of the enzyme without affecting its catalytic activity. However, truncation of 266, 272 and 273 amino acids resulted in a 70, 90 and >98% loss in catalytic activity. Interestingly, deletion of the single 12 amino acid motif G261KEAISALSRAK272 leads to a loss-of-function XT-I mutant. This is in agreement with our findings analysing the importance of the Cys residues where we have shown that C276A mutation resulted in a nearly inactive XT-I enzyme. Moreover, we investigated the location of the heparin-binding site of human XT-I using the truncated mutants. Heparin binding was observed to be slightly altered in mutants lacking 289 or 568 amino acids, but deletion of the potential heparin-binding motif P721KKVFKI727 did not lead to a loss of heparin binding capacity. The effect of heparin or UDP on the XT-I activity of all mutants was not significantly different from that of the wild-type. Our study demonstrates that over 80% of the nucleotide sequence of the XT-I-cDNA is necessary for expressing a recombinant enzyme with full catalytic activity.

FUNCTIONAL CHARACTERIZATION OF AN LCCL–LECTIN DOMAIN CONTAINING PROTEIN FAMILY IN PLASMODIUM BERGHEI

2004 ◽  
Vol 90 (5) ◽  
pp. 1062-1071 ◽  
Author(s):  
Holly E. Trueman ◽  
J. Dale Raine ◽  
Laurence Florens ◽  
Johannes T. Dessens ◽  
Jacqui Mendoza ◽  
...  
Keyword(s):  
Plasmodium Berghei ◽  
Functional Characterization ◽  
Protein Family ◽  
Lectin Domain

scholarly journals Functional characterization of constituent enzyme fractions of mycobacillin synthetase

1985 ◽  
Vol 230 (3) ◽  
pp. 785-789 ◽  
Author(s):  
S K Ghosh ◽  
S Majumder ◽  
N K Mukhopadhyay ◽  
S K Bose
Keyword(s):  
Amino Acids ◽  
Functional Characterization ◽  
Enzyme Fraction ◽  
Sequential Activation

The enzyme fraction A, a constituent enzyme of the three-fraction enzyme mycobacillin synthetase, independently and sequentially activated five amino acids starting from L-proline, producing the pentapeptide Pro(Asp1,Glu1,Tyr1)Asp. The fractions B and C were unable to function independently. However, the fraction B synthesized the nonapeptide Pro(Asp3,Glu1,Tyr2,Ser1)Leu, sequentially activating the pentapeptide and next four amino acids, whereas the fraction C synthesized mycobacillin by the sequential activation of the nonapeptide and the remaining four amino acids. The pH optima of the above enzymes are almost identical (pH 7.8), but their Km values are a little different.

Functional characterization of the transmembrane segment VII of the NHE1 isoform of the Na+/H+ exchangerThis paper is one of a selection of papers published in this Special Issue, entitled The Cellular and Molecular Basis of Cardiovascular Dysfunction, Dhalla 70th Birthday Tribute.

2007 ◽  
Vol 85 (3-4) ◽  
pp. 319-325 ◽  
Author(s):  
Jie Ding ◽  
Raymond W.P. Ng ◽  
Larry Fliegel
Keyword(s):  
Amino Acids ◽  
70Th Birthday ◽  
Functional Characterization ◽  
Integral Membrane Protein ◽  
Transmembrane Segment ◽  
Transmembrane Segments ◽  
Pore Lining ◽  
Positively Charged ◽  
Selection Of

The Na+/H+ exchanger isoform 1 is an integral membrane protein that regulates intracellular pH. It extrudes 1 intracellular H+ in exchange for 1 extracellular Na+. It has 2 large domains, an N-terminal membrane domain of 12 transmembrane segments and an intracellular C-terminal regulatory domain. We characterized the cysteine accessibility of amino acids of the critical transmembrane segment TM VII. Residues Leu 255, Leu 258, Glu 262, Leu 265, Asn 266, Asp 267, Val 269, Val 272, and Leu 273 were all mutated to cysteine residues in the cysteineless NHE1 isoform. Mutation of amino acids E262, N266, and D267 caused severe defects in activity and targeting of the intact full length protein. The balance of the active mutants were examined for sensitivity to the sulfhydryl reactive reagents, positively charged MTSET ((2- (trimethylammonium)ethyl)methanethiosulfonate) and negatively charged MTSES ((2-sulfonatoethyl)methanethiosulfonate). Leu 255 and Leu 258 were sensitive to MTSET but not to MTSES. The results suggest that these amino acids are pore-lining residues. We present a model of TM VII that shows that residues Leu 255, Leu 258, Glu 262, Asn 266, and Asp 267 lie near the same face of TM VII, lining the ion transduction pore.

scholarly journals Identification and Functional Characterization of the BAG Protein Family inArabidopsis thaliana

2006 ◽  
Vol 281 (27) ◽  
pp. 18793-18801 ◽  
Author(s):  
Elena V. Doukhanina ◽  
Shaorong Chen ◽  
Esther van der Zalm ◽  
Adam Godzik ◽  
John Reed ◽  
...  
Keyword(s):  
Functional Characterization ◽  
Protein Family

scholarly journals Structural and functional characterization of the two phosphoinositide binding sites of PROPPINs, a β-propeller protein family

2012 ◽  
Vol 109 (30) ◽  
pp. E2042-E2049 ◽  
Author(s):  
Roswitha Krick ◽  
Ricarda A. Busse ◽  
Andreea Scacioc ◽  
Milena Stephan ◽  
Andreas Janshoff ◽  
...  
Keyword(s):  
Binding Sites ◽  
Functional Characterization ◽  
Protein Family

scholarly journals AcpA, a member of the GPR1/FUN34/YaaH membrane protein family, is essential for acetate permease activity in the hyphal fungus Aspergillus nidulans

2008 ◽  
Vol 412 (3) ◽  
pp. 485-493 ◽  
Author(s):  
Xavier Robellet ◽  
Michel Flipphi ◽  
Sylvine Pégot ◽  
Andrew P. MacCabe ◽  
Christian Vélot
Keyword(s):  
Membrane Protein ◽  
Aspergillus Nidulans ◽  
Functional Characterization ◽  
Protein Family ◽  
Genome Data ◽  
Low Concentrations ◽  
Genes Encoding ◽  
Acetate Utilization ◽  
Utilization Pathway

In a previous study, alcS, a gene of the Aspergillus nidulans alc cluster, was shown to encode a protein that belongs to the GPR1/FUN34/YaaH membrane protein family. BLAST screening of the A. nidulans genome data identified additional genes encoding hypothetical proteins that could belong to this family. In this study we report the functional characterization of one of them, AN5226. Its expression is induced by ethanol and ethyl acetate (two inducers of the alc genes) and is mediated by the specific transcriptional activator of genes of the acetate-utilization pathway FacB. Growth of a null mutant (ΔAN5226) is notably affected when acetate is used as sole carbon source at low concentration and in a high pH medium, i.e. when protonated acetate, the form that can enter the cell by passive diffusion, is present in low amounts. Consistently, expression of AN5226 is also induced by acetate, but only when the latter is present at low concentrations. 14C-labelled acetate uptake experiments using germinating conidia demonstrate an essential role for AN5226 in mediated acetate transport. To our knowledge this report is the first to provide evidence for the identification of an acetate transporter in filamentous fungi. We have designated AN5226 as acpA (for acetate permease A).

Structural and functional characterization of complement c8γ, a member of the lipocalin protein family

1991 ◽  
Vol 28 (1-2) ◽  
pp. 123-131 ◽  
Author(s):  
Jacques-Antoine Haefliger ◽  
Manuel C. Peitsch ◽  
Dieter E. Jenne ◽  
Jürg Tschopp
Keyword(s):  
Functional Characterization ◽  
Protein Family
Sign in / Sign up

Export Citation Format

Share Document