Sequence analysis of bacterial redox enzyme maturation proteins (REMPs)

2004 ◽  
Vol 50 (4) ◽  
pp. 225-238 ◽  
Author(s):  
Raymond J Turner ◽  
Andriyka L Papish ◽  
Frank Sargent
Keyword(s):  
Nitrate Reductase ◽  
Protein Transport ◽  
Redox Enzyme ◽  
Respiratory Enzymes ◽  
Enzyme Maturation ◽  
Maturation Protein ◽  
Tat System ◽  
Folded Proteins ◽  
Sequence Relationships ◽  
Substrate Proteins

The twin-arginine protein transport (Tat) system is a remarkable molecular machine dedicated to the translocation of fully folded proteins across energy-transducing membranes. Complex cofactor-containing Tat substrates acquire their cofactors prior to export, and substrate proteins actually require to be folded before transport can proceed. Thus, it is very likely that mechanisms exist to prevent wasteful export of immature Tat substrates or to curb competition between immature and mature substrates for the transporter. Here we assess the primary sequence relationships between the accessory proteins implicated in this process during assembly of key respiratory enzymes in the model prokaryote Escherichia coli. For each respiratory enzyme studied, a redox enzyme maturation protein (REMP) was assigned. The main finding from this review was the hitherto unexpected link between the Tat-linked REMP DmsD and the nitrate reductase biosynthetic protein NarJ. The evolutionary link between Tat transport and cofactor insertion processes is discussed.Key words: Tat translocase, twin-arginine leader, hydrogenase, nitrate reductase, TMAO reductase, DMSO reductase, formate dehydrogenase, Tor, Dms, Hya, Hyb, Fdh, Nap.

scholarly journals A dual functional redox enzyme maturation protein for respiratory and assimilatory nitrate reductases in bacteria

2019 ◽  
Vol 111 (6) ◽  
pp. 1592-1603 ◽  
Author(s):  
Benjamin J. Pinchbeck ◽  
Manuel J. Soriano‐Laguna ◽  
Matthew J. Sullivan ◽  
Victor M. Luque‐Almagro ◽  
Gary Rowley ◽  
...  
Keyword(s):  
Redox Enzyme ◽  
Dual Functional ◽  
Enzyme Maturation ◽  
Maturation Protein ◽  
Nitrate Reductases

scholarly journals ‘Come into the fold’: A comparative analysis of bacterial redox enzyme maturation protein members of the NarJ subfamily

2014 ◽  
Vol 1838 (12) ◽  
pp. 2971-2984 ◽  
Author(s):  
Catherine S. Chan ◽  
Denice C. Bay ◽  
Thorin G.H. Leach ◽  
Tara M.L. Winstone ◽  
Lalita Kuzniatsova ◽  
...  
Keyword(s):  
Comparative Analysis ◽  
Redox Enzyme ◽  
Enzyme Maturation ◽  
Maturation Protein

scholarly journals Substrate-triggered position switching of TatA and TatB during Tat transport in Escherichia coli

Open Biology ◽  
2017 ◽  
Vol 7 (8) ◽  
pp. 170091 ◽  
Author(s):  
Johann Habersetzer ◽  
Kristoffer Moore ◽  
Jon Cherry ◽  
Grant Buchanan ◽  
Phillip J. Stansfeld ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Protein Transport ◽  
Cytoplasmic Membrane ◽  
Polar Cluster ◽  
Additional Sequence ◽  
Tat System ◽  
Folded Proteins ◽  
Related Proteins

The twin-arginine protein transport (Tat) machinery mediates the translocation of folded proteins across the cytoplasmic membrane of prokaryotes and the thylakoid membrane of plant chloroplasts. The Escherichia coli Tat system comprises TatC and two additional sequence-related proteins, TatA and TatB. The active translocase is assembled on demand, with substrate-binding at a TatABC receptor complex triggering recruitment and assembly of multiple additional copies of TatA; however, the molecular interactions mediating translocase assembly are poorly understood. A ‘polar cluster’ site on TatC transmembrane (TM) helix 5 was previously identified as binding to TatB. Here, we use disulfide cross-linking and molecular modelling to identify a new binding site on TatC TM helix 6, adjacent to the polar cluster site. We demonstrate that TatA and TatB each have the capacity to bind at both TatC sites, however in vivo this is regulated according to the activation state of the complex. In the resting-state system, TatB binds the polar cluster site, with TatA occupying the TM helix 6 site. However when the system is activated by overproduction of a substrate, TatA and TatB switch binding sites. We propose that this substrate-triggered positional exchange is a key step in the assembly of an active Tat translocase.

scholarly journals Variable stoichiometry of the TatA component of the twin-arginine protein transport system observed by in vivo single-molecule imaging

2008 ◽  
Vol 105 (40) ◽  
pp. 15376-15381 ◽  
Author(s):  
Mark C. Leake ◽  
Nicholas P. Greene ◽  
Rachel M. Godun ◽  
Thierry Granjon ◽  
Grant Buchanan ◽  
...  
Keyword(s):  
Single Molecule ◽  
Protein Transport ◽  
Fluorescent Protein ◽  
Yellow Fluorescent Protein ◽  
Protonmotive Force ◽  
Oligomeric State ◽  
Essential Components ◽  
Tat System ◽  
Folded Proteins

The twin-arginine translocation (Tat) system transports folded proteins across the bacterial cytoplasmic membrane and the thylakoid membrane of plant chloroplasts. The essential components of the Tat pathway are the membrane proteins TatA, TatB, and TatC. TatA is thought to form the protein translocating element of the Tat system. Current models for Tat transport make predictions about the oligomeric state of TatA and whether, and how, this state changes during the transport cycle. We determined the oligomeric state of TatA directly at native levels of expression in living cells by photophysical analysis of individual yellow fluorescent protein-labeled TatA complexes. TatA forms complexes exhibiting a broad range of stoichiometries with an average of ≈25 TatA subunits per complex. Fourier analysis of the stoichiometry distribution suggests the complexes are assembled from tetramer units. Modeling the diffusion behavior of the complexes suggests that TatA protomers associate as a ring and not a bundle. Each cell contains ≈15 mobile TatA complexes and a pool of ≈100 TatA molecules in a more disperse state in the membrane. Dissipation of the protonmotive force that drives Tat transport has no affect on TatA complex stoichiometry. TatA complexes do not form in cells lacking TatBC, suggesting that TatBC controls the oligomeric state of TatA. Our data support the TatA polymerization model for the mechanism of Tat transport.

scholarly journals Substrate-triggered position-switching of TatA and TatB is an essential step in the Escherichia coli Tat protein export pathway

2017 ◽  
Author(s):  
Johann Habersetzer ◽  
Kristoffer Moore ◽  
Jon Cherry ◽  
Grant Buchanan ◽  
Phillip Stansfeld ◽  
...  
Keyword(s):  
Escherichia Coli ◽  
Binding Sites ◽  
Protein Transport ◽  
Transmembrane Helix ◽  
Tat Protein ◽  
Disulfide Crosslinking ◽  
Additional Sequence ◽  
Tat System ◽  
Folded Proteins ◽  
Related Proteins

AbstractThe twin arginine protein transport (Tat) machinery mediates the translocation of folded proteins across the cytoplasmic membrane of prokaryotes and the thylakoid membrane of plant chloroplasts. The Escherichia coli Tat system comprises TatC and two additional sequence-related proteins, TatA and TatB. Here we use disulfide crosslinking and molecular modelling to show there are two binding sites for TatA/B proteins on TatC. TatA and TatB are each able to occupy both sites if they are the only TatA/B protein present. However, under resting conditions the sites are differentially occupied with TatB occupying the ‘polar cluster’ site while TatA binds adjacently at the TatC transmembrane helix 6 binding site. When the Tat system is activated by the overproduction of a substrate, TatA and TatB switch their binding sites. We propose that this substrate-triggered positional exchange is a key step in the assembly of an active Tat translocase.

scholarly journals Structural Basis of Type 2 Secretion System Engagement between the Inner and Outer Bacterial Membranes

mBio ◽  
2017 ◽  
Vol 8 (5) ◽  
Author(s):  
Iain D. Hay ◽  
Matthew J. Belousoff ◽  
Trevor Lithgow
Keyword(s):  
Outer Membrane ◽  
Protein Transport ◽  
Substrate Uptake ◽  
Inner Membrane ◽  
Protein Substrates ◽  
Folded Proteins ◽  
Membrane Components ◽  
Substrate Proteins ◽  
Vexing Question

ABSTRACT Sophisticated nanomachines are used by bacteria for protein secretion. In Gram-negative bacteria, the type 2 secretion system (T2SS) is composed of a pseudopilus assembly platform in the inner membrane and a secretin complex in the outer membrane. The engagement of these two megadalton-sized complexes is required in order to secrete toxins, effectors, and hydrolytic enzymes. Pseudomonas aeruginosa has at least two T2SSs, with the ancestral nanomachine having a secretin complex composed of XcpQ. Until now, no high-resolution structural information was available to distinguish the features of this Pseudomonas-type secretin, which varies greatly in sequence from the well-characterized Klebsiella-type and Vibrio-type secretins. We have purified the ~1-MDa secretin complex and analyzed it by cryo-electron microscopy. Structural comparisons with the Klebsiella-type secretin complex revealed a striking structural homology despite the differences in their sequence characteristics. At 3.6-Å resolution, the secretin complex was found to have 15-fold symmetry throughout the membrane-embedded region and through most of the domains in the periplasm. However, the N1 domain and N0 domain were not well ordered into this 15-fold symmetry. We suggest a model wherein this disordering of the subunit symmetry for the periplasmic N domains provides a means to engage with the 6-fold symmetry in the inner membrane platform, with a metastable engagement that can be disrupted by substrate proteins binding to the region between XcpP, in the assembly platform, and the XcpQ secretin. IMPORTANCE How the outer membrane and inner membrane components of the T2SS engage each other and yet can allow for substrate uptake into the secretin chamber has challenged the protein transport field for some time. This vexing question is of significance because the T2SS collects folded protein substrates in the periplasm for transport out of the bacterium and yet must discriminate these few substrate proteins from all the other hundred or so folded proteins in the periplasm. The structural analysis here supports a model wherein substrates must compete against a metastable interaction between XcpP in the assembly platform and the XcpQ secretin, wherein only structurally encoded features in the T2SS substrates compete well enough to disrupt XcpQ-XcpP for entry into the XcpQ chamber, for secretion across the outer membrane. IMPORTANCE How the outer membrane and inner membrane components of the T2SS engage each other and yet can allow for substrate uptake into the secretin chamber has challenged the protein transport field for some time. This vexing question is of significance because the T2SS collects folded protein substrates in the periplasm for transport out of the bacterium and yet must discriminate these few substrate proteins from all the other hundred or so folded proteins in the periplasm. The structural analysis here supports a model wherein substrates must compete against a metastable interaction between XcpP in the assembly platform and the XcpQ secretin, wherein only structurally encoded features in the T2SS substrates compete well enough to disrupt XcpQ-XcpP for entry into the XcpQ chamber, for secretion across the outer membrane.

scholarly journals The Tat-dependent protein translocation pathway

2011 ◽  
Vol 2 (6) ◽  
pp. 507-523 ◽  
Author(s):  
Bo Hou ◽  
Thomas Brüser
Keyword(s):  
Protein Transport ◽  
Protein Translocation ◽  
Transport Systems ◽  
Binding Motif ◽  
Twin Arginine Translocation ◽  
Multiple Copies ◽  
Dependent Protein ◽  
Tat System ◽  
Folded Proteins ◽  
Polytopic Membrane Protein

AbstractThe twin-arginine translocation (Tat) pathway is found in bacteria, archaea, and plant chloroplasts, where it is dedicated to the transmembrane transport of fully folded proteins. These proteins contain N-terminal signal peptides with a specific Tat-system binding motif that is recognized by the transport machinery. In contrast to other protein transport systems, the Tat system consists of multiple copies of only two or three usually small (∼8–30 kDa) membrane proteins that oligomerize to two large complexes that transiently interact during translocation. Only one of these complexes includes a polytopic membrane protein, TatC. The other complex consists of TatA. Tat systems of plants, proteobacteria, and several other phyla contain a third component, TatB. TatB is evolutionarily and structurally related to TatA and usually forms tight complexes with TatC. Minimal two-component Tat systems lacking TatB are found in many bacterial and archaeal phyla. They consist of a ‘bifunctional’ TatA that also covers TatB functionalities, and a TatC. Recent insights into the structure and interactions of the Tat proteins have various important implications.

An extremely SAD case: structure of a putative redox-enzyme maturation protein fromArchaeoglobus fulgidusat 3.4 Å resolution

2007 ◽  
Vol 63 (3) ◽  
pp. 348-354 ◽  
Author(s):  
Olga Kirillova ◽  
Maksymilian Chruszcz ◽  
Igor A. Shumilin ◽  
Tatiana Skarina ◽  
Elena Gorodichtchenskaia ◽  
...  
Keyword(s):  
Redox Enzyme ◽  
Enzyme Maturation ◽  
Maturation Protein ◽  
Case Structure

scholarly journals Substrate Proteins Take Shape at an Improved Bacterial Translocon

2018 ◽  
Vol 201 (1) ◽  
Author(s):  
Donald Oliver
Keyword(s):  
Protein Transport ◽  
Protein Translocation ◽  
Membrane Vesicles ◽  
Transport Models ◽  
Content Type ◽  
Rate Limiting ◽  
Substrate Proteins

ABSTRACTCharacterization of Sec-dependent bacterial protein transport has often relied on anin vitroprotein translocation system comprised in part ofEscherichia coliinverted inner membrane vesicles or, more recently, purified SecYEG translocons reconstituted into liposomes using mostly a single substrate (proOmpA). A paper published in this issue (P. Bariya and L. Randall, J Bacteriol 201:e00493-18, 2019, https://doi.org/10.1128/JB.00493-18) finds that inclusion of SecA protein during SecYEG proteoliposome reconstitution dramatically improves the number of active translocons. This experimentally useful and intriguing result that may arise from SecA membrane integration properties is discussed here. Furthermore, determination of the rate-limiting transport step for nine different substrates implicates the mature region distal to the signal peptide in the observed rate constant differences, indicating that more nuanced transport models that respond to differences in protein sequence and structure are needed.

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