scholarly journals Cell‐free production of integral membrane aspartic acid proteases reveals zinc‐dependent methyltransferase activity of the P seudomonas aeruginosa prepilin peptidase PilD

2012 ◽  
Vol 2 (1) ◽  
pp. 94-104 ◽  
Author(s):  
Khaled A. Aly ◽  
Emily T. Beebe ◽  
Chi H. Chan ◽  
Michael A. Goren ◽  
Carolina Sepúlveda ◽  
...  
2006 ◽  
Vol 188 (19) ◽  
pp. 6899-6914 ◽  
Author(s):  
Mladen Tomich ◽  
Daniel H. Fine ◽  
David H. Figurski

ABSTRACT The tad locus of Actinobacillus actinomycetemcomitans encodes genes for the biogenesis of Flp pili, which allow the bacterium to adhere tenaciously to surfaces and form strong biofilms. Although tad (tight adherence) loci are widespread among bacterial and archaeal species, very little is known about the functions of the individual components of the Tad secretion apparatus. Here we characterize the mechanism by which the pre-Flp1 prepilin is processed to the mature pilus subunit. We demonstrate that the tadV gene encodes a prepilin peptidase that is both necessary and sufficient for proteolytic maturation of Flp1. TadV was also found to be required for maturation of the TadE and TadF pilin-like proteins, which we term pseudopilins. Using site-directed mutagenesis, we show that processing of pre-Flp1, pre-TadE, and pre-TadF is required for biofilm formation. Mutation of a highly conserved glutamic acid residue at position +5 of Flp1, relative to the cleavage site, resulted in a processed pilin that was blocked in assembly. In contrast, identical mutations in TadE or TadF had no effect on biofilm formation, indicating that the mechanisms by which Flp1 pilin and the pseudopilins function are distinct. We also determined that two conserved aspartic acid residues in TadV are critical for function of the prepilin peptidase. Together, our results indicate that the A. actinomycetemcomitans TadV protein is a member of a novel subclass of nonmethylating aspartic acid prepilin peptidases.


2006 ◽  
Vol 188 (4) ◽  
pp. 1437-1443 ◽  
Author(s):  
Zalán Szabó ◽  
Sonja-Verena Albers ◽  
Arnold J. M. Driessen

ABSTRACT Archaeal preflagellin peptidases and bacterial type IV prepilin peptidases belong to a family of aspartic acid proteases that cleave the leader peptides of precursor proteins with type IV prepilin signal sequences. The substrate repertoire of PibD from the crenarchaeon Sulfolobus solfataricus is unusually diverse. In addition to flagellin, PibD cleaves three sugar-binding proteins unique to this species and a number of proteins with unknown function. Here we demonstrate that PibD contains two aspartic acid residues that are essential for cleavage activity. An additional pair of aspartic acids in a large cytoplasmic loop is also important for function and is possibly involved in leader peptide recognition. Combining the results of transmembrane segment predictions and cysteine-labeling experiments, we suggest a membrane topology model for PibD with the active-site aspartic acid residues exposed to the cytosol.


1996 ◽  
Vol 58 (6) ◽  
pp. 991-993
Author(s):  
Eishin MORITA ◽  
Susumu SHINODA ◽  
Eiichi GYOTOKU ◽  
Satoko HIHARA ◽  
Shoso YAMAMOTO

2009 ◽  
Vol 36 (8) ◽  
pp. 1056-1063
Author(s):  
Xiao-Hong QI ◽  
Xi-Min CHEN ◽  
Zhen-Qing FENG ◽  
Xiao-Hong GUAN ◽  
Jun WU ◽  
...  
Keyword(s):  

2009 ◽  
Vol 59 (12) ◽  
Author(s):  
Mihai Contineanu ◽  
iulia Contineanu ◽  
Ana Neacsu ◽  
Stefan Perisanu

The radiolysis of the isomers L-, D- and DL- of the aspartic acid, in solid polycrystalline state, was investigated at room temperature. The analysis of their ESR spectra indicated the formation of at least two radicalic entities. The radical, identified as R3, resulting from the deamination of the acid, exhibits the highest concentration and thermal resistance. Possible mechanisms of formation of three radical species are suggested, based also on literature data. The kinetics of the disappearance of radical R3 indicated a complex mechanism. Three possible variants were suggested for this mechanism.


2008 ◽  
Vol 59 (11) ◽  
Author(s):  
Iulia Lupan ◽  
Sergiu Chira ◽  
Maria Chiriac ◽  
Nicolae Palibroda ◽  
Octavian Popescu

Amino acids are obtained by bacterial fermentation, extraction from natural protein or enzymatic synthesis from specific substrates. With the introduction of recombinant DNA technology, it has become possible to apply more rational approaches to enzymatic synthesis of amino acids. Aspartase (L-aspartate ammonia-lyase) catalyzes the reversible deamination of L-aspartic acid to yield fumaric acid and ammonia. It is one of the most important industrial enzymes used to produce L-aspartic acid on a large scale. Here we described a novel method for [15N] L-aspartic synthesis from fumarate and ammonia (15NH4Cl) using a recombinant aspartase.


2011 ◽  
Vol 40 (12) ◽  
pp. 1720-1725
Author(s):  
Myoung-Gyu Park ◽  
Tae-Yul Ha ◽  
Kwang-Soon Shin

2015 ◽  
Vol 12 (2) ◽  
pp. 197-201 ◽  
Author(s):  
Liang Xi ◽  
Di Wu ◽  
Hong-You Zhu ◽  
Cong-Hai Zhang ◽  
Yi Jin ◽  
...  

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