eno

..Here we briefly review these findings and discuss their implications for understanding the multifaceted mechanisms controlling degradosome functions in vivo...

..In this minireview, our current understanding of structure/function relationships in the divergent members of the superfamily is reviewed, and the use of this knowledge for our future studies is proposed...

..Thus, RhlE can replace the function of RhlB in vitro. The results in the accompanying article show that CsdA can also replace RhlB in vitro. Thus, RhlB, RhlE and CsdA are interchangeable in in vitro RNA degradation assays...

..These findings show that the RNA degradosome is a flexible macromolecular machine capable of adapting to altered environmental conditions...

..In addition, we show that PNPase and RhlB within the degradosome cooperate to eliminate short degradation intermediates of ptsG mRNA...

..The carboxy-terminal domain of RNase E may thus act as a flexible tether of the degradosome components. The implications of these and other observations for the organization of the RNA degradosome are discussed...

....

....

..Although the catalytic domain of RNase E is sufficient for viability, our work demonstrates that elements in the non-catalytic part are necessary for normal activity in vivo...

..7 A from the closest phosphonate oxygen, and the loop (154-166) containing His 159 is shifted away from the active center. A peripheral loop, Glu 251-Gly 275, also moves to open access to the active site...

..We suggest that the chaperonin system may have facilitated the evolution of this fold into a versatile platform for the implementation of numerous enzymatic functions...

..sequences, two are associated with promoter regions of the gapA (glyceraldehyde 3-phosphate dehydrogenase) and eno (enolase) genes, both involved in sugar metabolism...

....

..The current model is that SgrS promotes recovery by stopping the synthesis of glucose transport proteins, which in turn limits the accumulation of toxic sugar-phosphates...

....

..9 A resolution is presented. The structure suggests that enolase may help to organize an adjacent conserved RNA-binding motif in RNase E...

..coli proteins, and the results are discussed in light of recent genomic profiling studies on the adaptive response of E. coli cells to stress by Zn(II) excess...

....

..We suggest that enolase is recruited into putative RNA degradosome machinery in these bacilli, where it plays common regulatory functions...

..e., 377-380 kDa), whereas no association between PNPase-alpha and enolase was detected. Chromosomal deletion of the eno gene had no effect on the ability of PNPase to degrade either single- or double-stranded RNAs...

..In addition, we show that normalized score values obtain by MudPIT analysis may be taken as quantitative estimates of the relative protein abundance in different degradosome preparations...

..RhlB in vitro can facilitate the degradation of structured RNA by PNPase. Since the discovery of the RNA degradosome in E. coli, related complexes have been described in other organisms...

..The putative role of enolase in the RNA degradosome is discussed; although it was not possible to ascribe a specific role to it, a structural role is possible...

..Our findings raise the prospect that E. coli proteins that bind to poly(A) tails may link the functions of degradosomes and ribosomes...

..The FLAG-Rne complex has RNase E activity in vivo and in vitro. The relative amount of proteins associated with wild-type and Rne-3071 expressed at an elevated temperature differed...

..These results suggest that RhlB acts by unwinding RNA structures that impede the processive activity of PNPase. RhlB is thus an important enzyme in mRNA turnover...

..The identification of a complex which includes several activities associated with mRNA degradation has implications for the mechanisms and co-ordinated control of mRNA degradation...

..The discovery of a specific association between RNAase E and PNPase raises the intriguing possibility that these enzymes act cooperatively in the processing and degradation of RNA...

..Translation of the gene eno, encoding enolase, is initiated 89 base pairs downstream of pyrG...

..Further analysis demonstrated loss of relA, fuc, and argA gene functions but retention of eno and recB, closely linked genes adjacent to relA and argA, respectively...

..isomerase (pgi), glucose-6-phosphate dehydrogenase (zwf), gluconate-6-phosphate dehydrogenase (gnd), enolase (eno), phosphoglycerate kinase (pgk), and fructose-1,6-P2 aldolase (fda)...

..RNase E and PNPase of the multiprotein complex presumably cooperate for effective processing and turnover of specific substrates, such as mRNAs and other RNAs in vivo...

The entire Escherichia coli eno gene was cloned by functional complementation of a newly isolated temperature-sensitive enolase mutant and its nucleotide sequence determined...

..Thus, PPK in the degradosome appears to maintain an appropriate microenvironment, removing inhibitory polyphosphate and NDPs and regenerating ATP...

..Our findings, which establish the existence and cellular location of RNase E-based degradosomes in vivo in E. coli, also suggest that RNA processing and decay may occur at specific sites within cells...

..coli, also has the previously unsuspected ability to affect protein degradation through its role in maturation of the 3' end of ssrA RNA...

..A model for degradosome-mediated degradation of structured RNA is presented with its implications for mRNA decay in Escherichia coli...

..The inaccessibility of 3'-oligo(U) sequences is likely to have a role in stabilization of RNA molecules generated by Rho-independent terminators...

..of tryptophanase (trpA), citrate synthase (gltA), and aldehyde dehydrogenase (aldA) and the repression of enolase (eno) and phosphoglycerate kinase (pgk) were observed...

....

..Moreover, decay of a model mRNA can be reconstituted in vitro by a small number of purified components in a process which is more dynamic and ATP-dependent than previously imagined...

..Our results, which provide evidence that decay of mature rRNAs occurs in growing Escherichia coli cells in the RNA degradosome, implicate RNase E in degradosome-mediated decay...

..The K341E mutant enolase was almost as active as the wild-type enzyme and therefore allowed us to establish that the loss of enolase export correlates with the loss of modification and not the loss of glycolytic activity...

..Complete reversal of the changes in activity was possible by adding an aliquot of partially purified enolase kinase plus ATP...

..Through the use of two-dimensional gel electrophoresis, we were able to show that the levels of OmpF, AspC, YcdO, Eno, and CysE increased after 30 min of Zn(II) stress, while the levels of Tig, TufA, SelA, and LeuC decreased relative ..

..4) A structural blueprint for functional diversity in the ((beta/alpha)8-barrel fold will be tested. ..

..4) We will test a structural blueprint for functional diversity in the (beta/alpha)7beta-barrel fold by determining whether new functions can be generated by in vitro evolution. ..

....

..Studies of SgrS in particular are important since SgrS is the first member of a novel class of bifunctional sRNA regulators and therefore serves as a model for other similar sRNAs that will be identified in the future. ..

..5) 3-OH Isobutyryl CoA hydrolase (HIBCH) catalyzes hydrolysis of a thioester in valine catabolism. We will study HIBCH so that we can determine whether the reaction proceeds via and enolate anion or an anionic tetrahedral intermediate. ..

..Dr. Gerlt and his group will investigate the mechanism of this reaction so that they can better understand the underlying catalytic strategy used by the members of the superfamily. ..

....