The 16-kDa α-crystallin-like protein of Mycobacterium bovis BCG is produced under conditions of oxygen deficiency and is associated with ribosomes

Tabira, Yasuhiro; Ohara, Naoya; Kitaura, Hideki; Matsumoto, Sohkichi; Naito, Mariko; Yamada, Takeshi

doi:10.1016/s0923-2508(98)80301-x

Cited by 16 publications

(7 citation statements)

References 10 publications

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“…In retrospect, Hsp16.3, an sHSP of Mycobacterium tuberculosis, was found to be associated with ribosomes, either in cells grown under oxygen-deficient conditions as reported by Tabira et al [57] or in the in vitro transcription/translation system as reported by our laboratory [86]. It appears that bacterial sHSPs preferentially protect the protein synthesis machine under stress conditions.…”

Section: Functional Preference Of the Substrate Proteins Of Shspssupporting

confidence: 62%

“…As such, sHSPs could act as robust chaperones under fluctuating conditions and enhance their chaperone activities at elevating temperatures. Importantly, accumulative evidence indicate that sHSPs also preferentially protect certain classes of functional proteins, such as translation-related proteins and metabolic enzymes [54,[56][57][58]. In this review, I will focus on how an sHSP activates its numerous multi-type substrate-binding residues and what functional proteins it protects in cells.…”

Section: Introductionmentioning

confidence: 99%

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Chaperone function and mechanism of small heat-shock proteins

Fu¹

2014

ABBS

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Small heat-shock proteins (sHSPs) are ubiquitous ATP-independent molecular chaperones that play crucial roles in protein quality control in cells. They are able to prevent the aggregation and/or inactivation of various non-native substrate proteins and assist the refolding of these substrates independently or under the help of other ATP-dependent chaperones. Substrate recognition and binding by sHSPs are essential for their chaperone functions. This review focuses on what natural substrate proteins an sHSP protects and how it binds the substrates in cells under fluctuating conditions. It appears that sHSPs of prokaryotes, although being able to bind a wide range of cellular proteins, preferentially protect certain classes of functional proteins, such as translation-related proteins and metabolic enzymes, which may well explain why they could increase the resistance of host cells against various stresses. Mechanistically, the sHSPs of prokaryotes appear to possess numerous multi-type substrate-binding residues and are able to hierarchically activate these residues in a temperature-dependent manner, and thus act as temperature-regulated chaperones. The mechanism of hierarchical activation of substrate-binding residues is also discussed regarding its implication for eukaryotic sHSPs.

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Section: Functional Preference Of the Substrate Proteins Of Shspssupporting

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Chaperone function and mechanism of small heat-shock proteins

Fu¹

2014

ABBS

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“…Further, spot 8 corresponding to Rv2031c encodes 14 kDa antigen (HSP16.3/HSPX) which is a member of the small heat-shock protein family of chaperones. It has been shown to be induced under oxygen-deficient conditions [17]. Its role in maintenance of long term viability during latent, asymptomatic infections and in replication during initial infection has also been proposed.…”

Section: Discussionmentioning

confidence: 99%

Proteomic analysis of streptomycin resistant and sensitive clinical isolates of Mycobacterium tuberculosis

et al. 2010

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BackgroundStreptomycin (SM) is a broad spectrum antibiotic and is an important component of any anti-tuberculosis therapy regimen. Several mechanisms have been proposed to explain the emergence of resistance but still our knowledge is inadequate. Proteins form a very complex network and drugs are countered by their modification/efflux or over expression/modification of targets. As proteins manifest most of the biological processes, these are attractive targets for developing drugs, immunodiagnostics or therapeutics. The aim of present study was to analyze and compare the protein profile of whole cell extracts from Mycobacterium tuberculosis clinical isolates susceptible and resistant to SM.ResultsTwo-dimensional gel electrophoresis (2DE) and matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry was employed for analyzing the protein profiles. Homology and in silico characterization for identified proteins was assessed using BLAST, InterProScan and KEGG database searches. Computational studies on the possible interactions between SM and identified proteins were carried out by a battery of online servers and softwares, namely, CLUSTALW (KEGG), I-TASSER, VMD, PatchDock and FireDock. On comparing 2DE patterns, nine proteins were found consistently overexpressed in SM resistant isolates and were identified as Rv0350, Rv0440, Rv1240, Rv3075c, Rv2971, Rv3028c, Rv2145c, Rv2031c and Rv0569. In silico docking analysis showed significant interactions of SM with essential (Rv0350, Rv0440 and Rv2971) and non essential (Rv1240, Rv3075c and Rv2031c) genes.ConclusionsThe computational results suggest high protein binding affinity of SM and suggested many possible interactions between identified proteins and the drug. Bioinformatic analysis proves attributive for analysis of diversity of proteins identified by whole proteome analysis. In-depth study of the these proteins will give an insight into probable sites of drug action other than established primary sites and hence may help in search of novel chemotherapeutic agents at these new sites as inhibitors.

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“…The suspension culture in the glycerol-based medium is therefore likely to create limitation in oxygen supply with subsequent consequences for the protein expression profile. ESAT-6 is one of the proteins that are expressed when exposing bacilli to low oxygen tension along with several other proteins, such as alpha crystalline [23,24]. The basic question is whether ESAT-6 and other proteins such as heat-shock proteins that also are present in short-term culture filtrates, appear as a result of specific secretion or as a result of the more unspecific release from cells with damaged or disintegrated cytoplasmic membranes.…”

Section: Comparison Of the Short-term Culture Approach And The Localimentioning

confidence: 99%

Liberation of Soluble Proteins from Live and Dead Mycobacterial Cells and the Implications for Pathogenicity of Tubercle Bacilli

Wiker¹

2001

Scand J Immunol

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Soluble proteins liberated from live M. tuberculosis are translocated through the cytoplasmic membrane to à periplasmic space'. For further export of proteins across the outer permeability barrier, it is necessary to postulate an excretion mechanism possibly involving some kind of porin. Observations of the repertoire of proteins in culture filtrates after liquid culture of M. tuberculosis show that a large repertoire of various kinds of proteins cross the outer permeability barrier of tubercle bacilli indicating that the excretion mechanism has a wide range of specificities for proteins. Culture filtrates of tubercle bacilli almost always contain both truly secreted proteins and cytoplasmatically-derived proteins. It is questionable whether cytoplasmic proteins can cross an intact cytoplasmic membrane. The simplest explanation for the appearance of cytoplasmic proteins in culture filtrates of tubercle bacilli would be that they are released after disintegration of the cytoplasmic membrane in dying or dead bacilli. Tubercle bacilli armed with secreted factors that may specifically inhibit innate and adaptive immune responses, excrete these from the periplasmic space of live bacilli. Unspecific in its character, the excretion mechanism also liberates proteins that are essential for building and maintaining the cell wall, thereby reducing the effectiveness of this process. This may be part of the explanation why M. tuberculosis and other pathogenic mycobacteria grow so slowly. Finally, it may be postulated that dormant or latent tubercle bacilli use their repertoire of secreted proteins to control their intracellular habitat and that bacterial cytoplasmic proteins would not be liberated from such bacilli. The consequence would be that only immune responses to secreted proteins would be effective for elimination of the dormant stage of infection. In a situation with active infection there will be considerable growth and turnover of bacilli with liberation of all kinds of immunogenic substances from the bacilli. In this situation immunity against cytoplasmic proteins would also be effective and immunity to cytoplasmic proteins should also be effective for control of the reactivation of latent disease because as soon as the bacilli start to grow there will also be a subpopulation of dead bacilli on the arena. THE ENVELOPE OF MYCOBACTERIACompared to many other bacterial genera, the outer permeability barrier of mycobacteria is extremely tight and particularly so for M. tuberculosis [1,2]. This is owing to the unusual structure of the mycobacterial cell wall which is highly impermeable to hydrophilic solutes. Hydrophobic solutes can penetrate the barrier [1]. Antibiotics of the most hydrophobic types for example, are also the most effective drugs against mycobacteria [3,4].Considering the extreme rigidity and impermeability of the outer permeability barrier [5] of M. tuberculosis, it is a paradox that liquid cultures contain excessive amounts of soluble proteins which are much larger than the small solutes referred to...

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The 16-kDa α-crystallin-like protein of Mycobacterium bovis BCG is produced under conditions of oxygen deficiency and is associated with ribosomes

Cited by 16 publications

References 10 publications

Chaperone function and mechanism of small heat-shock proteins

Chaperone function and mechanism of small heat-shock proteins

Proteomic analysis of streptomycin resistant and sensitive clinical isolates of Mycobacterium tuberculosis

Liberation of Soluble Proteins from Live and Dead Mycobacterial Cells and the Implications for Pathogenicity of Tubercle Bacilli

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