Crystal stuctures of MglB‐2 (TP0684), a topologically variant <scp>d</scp>‐glucose‐binding protein from <i>Treponema pallidum,</i> reveal a ligand‐induced conformational change

Brautigam, Chad A.; Deka, Ranjit K.; Liu, Wei Z.; Norgard, Michael V.

doi:10.1002/pro.3373

Cited by 4 publications

(3 citation statements)

References 21 publications

(49 reference statements)

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“…As an approach to circumvent historic research barriers and to elucidate previously unappreciated molecular and mechanistic features of T. pallidum , we have focused on discerning salient structure-function relationships for T. pallidum ’s membrane lipoproteins (LPs) ( 7 , 17 – 31 ). Membrane LPs serve many key functions in pathogenic bacteria ( 32 , 33 ), and numerous studies point to the importance of LPs in crucial aspects of T. pallidum biology (about 4.4% of T. pallidum ’s genome encodes 48 or more LPs) ( 34 , 35 ).…”

Section: Introductionmentioning

confidence: 99%

“…Membrane LPs serve many key functions in pathogenic bacteria ( 32 , 33 ), and numerous studies point to the importance of LPs in crucial aspects of T. pallidum biology (about 4.4% of T. pallidum ’s genome encodes 48 or more LPs) ( 34 , 35 ). Our discovery-driven approach has involved characterizing recombinant versions of the treponemal LPs using structural biology, protein biophysics, and biochemistry ( 17 – 31 , 36 ). These efforts have led to a number of novel discoveries for T. pallidum ( 17 , 21 – 23 , 25 – 28 , 30 ), some of which are applicable to other bacteria ( 22 , 23 , 25 , 27 – 29 , 36 – 39 ).…”

Section: Introductionmentioning

confidence: 99%

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Biophysical and Biochemical Characterization of TP0037, a d -Lactate Dehydrogenase, Supports an Acetogenic Energy Conservation Pathway in Treponema pallidum

Deka

Liu

Norgard

et al. 2020

mBio

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A longstanding conundrum in Treponema pallidum biology concerns how the spirochete generates sufficient energy to fulfill its complex pathogenesis processes during human syphilitic infection. For decades, it has been assumed that the bacterium relies solely on glucose catabolism (via glycolysis) for generation of its ATP. However, the organism’s robust motility, believed to be essential for human tissue invasion and dissemination, would require abundant ATP likely not provided by the parsimony of glycolysis. As such, additional ATP generation, either via a chemiosmotic gradient, substrate-level phosphorylation, or both, likely exists in T. pallidum. Along these lines, we have hypothesized that T. pallidum exploits an acetogenic energy conservation pathway that relies on the redox chemistry of flavins. Central to this hypothesis is the apparent existence in T. pallidum of an acetogenic pathway for the conversion of d-lactate to acetate. Herein we have characterized the structural, biophysical, and biochemical properties of the first enzyme (d-lactate dehydrogenase [d-LDH]; TP0037) predicted in this pathway. Binding and enzymatic studies showed that recombinant TP0037 consumed d-lactate and NAD+ to produce pyruvate and NADH. The crystal structure of TP0037 revealed a fold similar to that of other d-acid dehydrogenases; residues in the cofactor-binding and active sites were homologous to those of other known d-LDHs. The crystal structure and solution biophysical experiments revealed the protein’s propensity to dimerize, akin to other d-LDHs. This study is the first to elucidate the enzymatic properties of T. pallidum’s d-LDH, thereby providing new compelling evidence for a flavin-dependent acetogenic energy conservation (ATP-generating) pathway in T. pallidum. IMPORTANCE Because T. pallidum lacks a Krebs cycle and the capability for oxidative phosphorylation, historically it has been difficult to reconcile how the syphilis spirochete generates sufficient ATP to fulfill its energy needs, particularly for its robust motility, solely from glycolysis. We have postulated the existence in T. pallidum of a flavin-dependent acetogenic energy conservation pathway that would generate additional ATP for T. pallidum bioenergetics. In the proposed acetogenic pathway, first d-lactate would be converted to pyruvate. Pyruvate would then be metabolized to acetate in three additional steps, with ATP being generated via substrate-level phosphorylation. This study provides structural, biochemical, and biophysical evidence for the first T. pallidum enzyme in the pathway (TP0037; d-lactate dehydrogenase) requisite for the conversion of d-lactate to pyruvate. The findings represent the first experimental evidence to support a role for an acetogenic energy conservation pathway that would contribute to nonglycolytic ATP production in T. pallidum.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Biophysical and Biochemical Characterization of TP0037, a d -Lactate Dehydrogenase, Supports an Acetogenic Energy Conservation Pathway in Treponema pallidum

Deka

Liu

Norgard

et al. 2020

mBio

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“…Of the remaining 13, some may be good candidates for having surface exposure, a highly sought-after property in this spirochete. Of the 28 IM lipoproteins, MglB (TDE2217), TmpC (TDE1950) and peptide transport systems involving OppA (TDE1071) and DppA (TDE1072) have been characterized in T. denticola , and 10 homologues of the IM lipoproteins were found in T. pallidum including five that have been characterized to our knowledge (Table S2 − ). In E. coli , lipoproteins are sorted between IM and OM locations by the presence of an Asp residue in the +2 position relative to the signal peptide cleavage site.…”

Section: Discussionmentioning

confidence: 99%

Localization of Outer Membrane Proteins in Treponema denticola by Quantitative Proteome Analyses of Outer Membrane Vesicles and Cellular Fractions

et al. 2019

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The identification and localization of outer membrane proteins (Omps) and lipoproteins in pathogenic treponemes such as T. denticola (periodontitis) and T. pallidum (syphilis) has been challenging. In this study, label-free quantitative proteomics using MaxQuant was applied to naturally produced outer membrane vesicles (OMVs) and cellular fractions to identify 1448 T. denticola proteins. Of these, 90 proteins were localized to the outer membrane (OM) comprising 59 lipoproteins, 25 β-barrel proteins, and six other putative OM-associated proteins. Twenty-eight lipoproteins were localized to the inner membrane (IM), and 43 proteins were assigned to the periplasm. The signal cleavage regions of the OM and IM lipoprotein sequences were different and may reveal the signals for their differential localization. Proteins significantly enriched in OMVs included dentilisin, proteins containing leucine-rich repeats, and several lipoproteins containing FGE-sulfatase domains. Blue native PAGE analysis enabled the native size of the dentilisin complex and Msp to be determined and revealed that the abundant β-barrel Omps TDE2508 and TDE1717 formed large complexes. In addition to the large number of integral Omps and potentially surface-located lipoproteins identified in T. denticola, many such proteins were also newly identified in T. pallidum through homology, generating new targets for vaccine development in both species.

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Using modern approaches to sedimentation velocity to detect conformational changes in proteins

et al. 2020

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Crystal stuctures of MglB‐2 (TP0684), a topologically variant d‐glucose‐binding protein from Treponema pallidum, reveal a ligand‐induced conformational change

Cited by 4 publications

References 21 publications

Biophysical and Biochemical Characterization of TP0037, a d -Lactate Dehydrogenase, Supports an Acetogenic Energy Conservation Pathway in Treponema pallidum

Biophysical and Biochemical Characterization of TP0037, a d -Lactate Dehydrogenase, Supports an Acetogenic Energy Conservation Pathway in Treponema pallidum

Localization of Outer Membrane Proteins in Treponema denticola by Quantitative Proteome Analyses of Outer Membrane Vesicles and Cellular Fractions

Using modern approaches to sedimentation velocity to detect conformational changes in proteins

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