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Baischew A, Engel S, Geiger TM, Taubert MC, Hausch F. Structural and biochemical insights into FKBP51 as a Hsp90 co-chaperone. J Cell Biochem 2023. [PMID: 36791213 DOI: 10.1002/jcb.30384] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Revised: 01/16/2023] [Accepted: 01/30/2023] [Indexed: 02/17/2023]
Abstract
The FK506-binding protein 51 (FKBP51) is a high-molecular-weight immunophilin that emerged as an important drug target for stress-related disorders, chronic pain, and obesity. It has been implicated in a plethora of molecular pathways but remains best characterized as a co-chaperone of Hsp90 in the steroid hormone receptor (SHR) maturation cycle. However, the mechanistic and structural basis for the regulation of SHRs by FKBP51 and the usually antagonistic function compared with its closest homolog FKBP52 remains enigmatic. Here we review recent structural and biochemical studies of FKBPs as regulators in the Hsp90 machinery. These advances provide important insights into the roles of FKBP51 and FKBP52 in SHR regulation.
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Affiliation(s)
- Asat Baischew
- Department of Chemistry, Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Sarah Engel
- Department of Chemistry, Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Thomas M Geiger
- Department of Chemistry, Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Martha C Taubert
- Department of Chemistry, Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
| | - Felix Hausch
- Department of Chemistry, Institute for Organic Chemistry and Biochemistry, Technical University Darmstadt, Darmstadt, Germany
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2
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Barik S. An Analytical Review of the Structural Features of Pentatricopeptide Repeats: Strategic Amino Acids, Repeat Arrangements and Superhelical Architecture. Int J Mol Sci 2021; 22:ijms22105407. [PMID: 34065603 PMCID: PMC8160929 DOI: 10.3390/ijms22105407] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2021] [Revised: 05/18/2021] [Accepted: 05/19/2021] [Indexed: 12/27/2022] Open
Abstract
Tricopeptide repeats are common in natural proteins, and are exemplified by 34- and 35-residue repeats, known respectively as tetratricopeptide repeats (TPRs) and pentatricopeptide repeats (PPRs). In both classes, each repeat unit forms an antiparallel bihelical structure, so that multiple such units in a polypeptide are arranged in a parallel fashion. The primary structures of the motifs are nonidentical, but amino acids of similar properties occur in strategic positions. The focus of the present work was on PPR, but TPR, its better-studied cousin, is often included for comparison. The analyses revealed that critical amino acids, namely Gly, Pro, Ala and Trp, were placed at distinct locations in the higher order structure of PPR domains. While most TPRs occur in repeats of three, the PPRs exhibited a much greater diversity in repeat numbers, from 1 to 30 or more, separated by spacers of various sequences and lengths. Studies of PPR strings in proteins showed that the majority of PPR units are single, and that the longer tandems (i.e., without space in between) occurred in decreasing order. The multi-PPR domains also formed superhelical vortices, likely governed by interhelical angles rather than the spacers. These findings should be useful in designing and understanding the PPR domains.
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Affiliation(s)
- Sailen Barik
- EonBio, 3780 Pelham Drive, Mobile, AL 36619, USA
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3
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Wisser CS, Thaler Neto A, Batista HB, Mori E, Chierato ME, Fernandes ME, Traverso SD. Cattle rabies: the effect of clinical evolution, viral genetic lineage, and viral load on the severity of histological lesions. PESQUISA VETERINÁRIA BRASILEIRA 2020. [DOI: 10.1590/1678-5150-pvb-6438] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
ABSTRACT: Our objective was the characterization and staging of histological lesions in different anatomical sites of the central nervous system (CNS) of rabid cattle. The severity of the lesions was compared with the clinical stages of the disease, the variants of viral isolates, and with the load of virus. Thirty-one spontaneously affected rabid cattle the state of Santa Catarina underwent clinical follow-up and were eventually necropsied. CNS tissues were sampled and submitted to direct fluorescent antibody technique (DFAT), immunohistochemistry (IHC), routine histopathology with hematoxylin and eosin stain (HE), reverse transcriptase polymerase chain reaction (RT-PCR), and polymerase chain reaction in quantitative reverse transcriptase in real time (qRT-PCR). Affected cattle were allotted in four groups according to their clinical stage when euthanized: G1, euthanized while standing; G2, euthanized when in sternal recumbence; G3, euthanized when in lateral recumbence; and G4, affected cattle with natural death. In order to evaluate the degree of severity of the lesions and the presence of Negri bodies (NBs), the brain was sectioned at 9 sites. Additionally, spinal cord and trigeminal ganglion sections were examined. The intensity of the lesions was graded as either absent, mild, moderate, or marked, and the presence or absence of the NBs was noted. Histological lesions were characterized by lymphocytic and monocytic meningoencephalitis with NBs in 28 cases. In all analyzed groups, intensities of histological lesions ranging from mild to severe were observed. Brain regions with the highest inflammatory lesion intensity were the medulla at the level of obex, followed by the colliculus and thalamus. NBs were observed in a higher percentage in the cerebellum, followed by medulla at the obex level, striatum complex, and frontal telencephalon. The duration of the clinical course of the disease did not influence the intensity of the inflammatory lesion, but it did influence the presence of NBs, with a higher percentage of these inclusions in cattle that died naturally than in euthanized cattle. All isolated rhabdovirus included in this study were genetically compatible with samples from hematophagous bats Desmodus rotundus. The evaluation by qRT-PCR did not demonstrate a correlation between lesion intensity and the amount of virus.
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Affiliation(s)
| | | | | | - Enio Mori
- Instituto Pasteur de São Paulo, Brazil
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4
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Kalel VC, Mäser P, Sattler M, Erdmann R, Popowicz GM. Come, sweet death: targeting glycosomal protein import for antitrypanosomal drug development. Curr Opin Microbiol 2018; 46:116-122. [PMID: 30481613 DOI: 10.1016/j.mib.2018.11.003] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 11/09/2018] [Indexed: 01/18/2023]
Abstract
Glycosomes evolved as specialized system for glycolysis in trypanosomatids. These organelle rely on protein import to maintain function. A machinery of peroxin (PEX) proteins is responsible for recognition and transport of glycosomal proteins to the organelle. Disruption of PEX-based import system was expected to be a strategy against trypanosomatids. Recently, a proof of this hypothesis has been presented. Here, we review current information about trypanosomatids' glycosomal transport components as targets for new trypanocidal therapies.
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Affiliation(s)
- Vishal C Kalel
- Institute of Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University Bochum, 44780 Bochum, Germany
| | - Pascal Mäser
- Swiss Tropical and Public Health Institute, Socinstrasse 57, 4051 Basel, Switzerland; University of Basel, 4001 Basel, Switzerland
| | - Michael Sattler
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; Center for Integrated Protein Science Munich at Chair of Biomolecular NMR, Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany
| | - Ralf Erdmann
- Institute of Biochemistry and Pathobiochemistry, Department of Systems Biochemistry, Faculty of Medicine, Ruhr University Bochum, 44780 Bochum, Germany
| | - Grzegorz M Popowicz
- Institute of Structural Biology, Helmholtz Zentrum München, Ingolstädter Landstr. 1, 85764 Neuherberg, Germany; Center for Integrated Protein Science Munich at Chair of Biomolecular NMR, Department Chemie, Technische Universität München, Lichtenbergstr. 4, 85747 Garching, Germany.
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5
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Watanabe Y, Kawaguchi K, Okuyama N, Sugawara Y, Obita T, Mizuguchi M, Morita M, Imanaka T. Characterization of the interaction betweenTrypanosoma bruceiPex5p and its receptor Pex14p. FEBS Lett 2016; 590:242-50. [DOI: 10.1002/1873-3468.12044] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2015] [Revised: 12/05/2015] [Accepted: 12/07/2015] [Indexed: 11/09/2022]
Affiliation(s)
- Yuichi Watanabe
- Department of Biological Chemistry; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Kosuke Kawaguchi
- Department of Biological Chemistry; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Naoki Okuyama
- Department of Biological Chemistry; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Yuri Sugawara
- Department of Structural Biology; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Takayuki Obita
- Department of Structural Biology; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Mineyuki Mizuguchi
- Department of Structural Biology; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Masashi Morita
- Department of Biological Chemistry; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
| | - Tsuneo Imanaka
- Department of Biological Chemistry; Graduate School of Medicine and Pharmaceutical Sciences; University of Toyama; Sugitani Japan
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6
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Hagen S, Drepper F, Fischer S, Fodor K, Passon D, Platta HW, Zenn M, Schliebs W, Girzalsky W, Wilmanns M, Warscheid B, Erdmann R. Structural insights into cargo recognition by the yeast PTS1 receptor. J Biol Chem 2015; 290:26610-26. [PMID: 26359497 DOI: 10.1074/jbc.m115.657973] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2015] [Indexed: 11/06/2022] Open
Abstract
The peroxisomal matrix protein import is facilitated by cycling import receptors that shuttle between the cytosol and the peroxisomal membrane. The import receptor Pex5p mediates the import of proteins harboring a peroxisomal targeting signal of type I (PTS1). Purified recombinant Pex5p forms a dimeric complex with the PTS1-protein Pcs60p in vitro with a KD of 0.19 μm. To analyze the structural basis for receptor-cargo recognition, the PTS1 and adjacent amino acids of Pcs60p were systematically scanned for Pex5p binding by an in vitro site-directed photo-cross-linking approach. The cross-linked binding regions of the receptor were subsequently identified by high resolution mass spectrometry. Most cross-links were found with TPR6, TPR7, as well as the 7C-loop of Pex5p. Surface plasmon resonance analysis revealed a bivalent interaction mode for Pex5p and Pcs60p. Interestingly, Pcs60p lacking its C-terminal tripeptide sequence was efficiently cross-linked to the same regions of Pex5p. The KD value of the interaction of truncated Pcs60p and Pex5p was in the range of 7.7 μm. Isothermal titration calorimetry and surface plasmon resonance measurements revealed a monovalent binding mode for the interaction of Pex5p and Pcs60p lacking the PTS1. Our data indicate that Pcs60p contains a second contact site for its receptor Pex5p, beyond the C-terminal tripeptide. The physiological relevance of the ancillary binding region was supported by in vivo import studies. The bivalent binding mode might be explained by a two-step concept as follows: first, cargo recognition and initial tethering by the PTS1-receptor Pex5p; second, lock-in of receptor and cargo.
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Affiliation(s)
- Stefanie Hagen
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Friedel Drepper
- the Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signaling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Sven Fischer
- the Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signaling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Krisztian Fodor
- the Department of Biochemistry, Eötvös Loránd University, H-1117 Budapest, Hungary
| | - Daniel Passon
- the European Molecular Biology Laboratory at Hamburg, D-22607 Hamburg, Germany
| | - Harald W Platta
- the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, Biochemistry of Intracellular Transport Mechanism, Ruhr-University Bochum, D-44781 Bochum, Germany, and
| | - Michael Zenn
- the Biaffin GmbH and Co., KG, D-34132 Kassel, Germany
| | - Wolfgang Schliebs
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Wolfgang Girzalsky
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany
| | - Matthias Wilmanns
- the European Molecular Biology Laboratory at Hamburg, D-22607 Hamburg, Germany
| | - Bettina Warscheid
- the Department of Biochemistry and Functional Proteomics, Faculty of Biology and BIOSS Centre for Biological Signaling Studies, University of Freiburg, D-79104 Freiburg, Germany
| | - Ralf Erdmann
- From the Institute of Biochemistry and Pathobiochemistry, Faculty of Medicine, System Biochemistry, Ruhr-University Bochum, D-44780 Bochum, Germany,
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7
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Wiech EM, Cheng HP, Singh SM. Molecular modeling and computational analyses suggests that the Sinorhizobium meliloti periplasmic regulator protein ExoR adopts a superhelical fold and is controlled by a unique mechanism of proteolysis. Protein Sci 2015; 24:319-27. [PMID: 25492513 PMCID: PMC4353358 DOI: 10.1002/pro.2616] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2014] [Revised: 11/26/2014] [Accepted: 12/01/2014] [Indexed: 12/12/2022]
Abstract
The Sinorhizobium meliloti periplasmic ExoR protein and the ExoS/ChvI two-component system form a regulatory mechanism that directly controls the transformation of free-living to host-invading cells. In the absence of crystal structures, understanding the molecular mechanism of interaction between ExoR and the ExoS sensor, which is believed to drive the key regulatory step in the invasion process, remains a major challenge. In this study, we present a theoretical structural model of the active form of ExoR protein, ExoRm , generated using computational methods. Our model suggests that ExoR possesses a super-helical fold comprising 12 α-helices forming six Sel1-like repeats, including two that were unidentified in previous studies. This fold is highly conducive to mediating protein-protein interactions and this is corroborated by the identification of putative protein binding sites on the surface of the ExoRm protein. Our studies reveal two novel insights: (a) an extended conformation of the third Sel1-like repeat that might be important for ExoR regulatory function and (b) a buried proteolytic site that implies a unique proteolytic mechanism. This study provides new and interesting insights into the structure of S. meliloti ExoR, lays the groundwork for elaborating the molecular mechanism of ExoRm cleavage, ExoRm -ExoS interactions, and studies of ExoR homologs in other bacterial host interactions.
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Affiliation(s)
- Eliza M Wiech
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
| | - Hai-Ping Cheng
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Biological Sciences Department, Lehman College, The City University of New YorkBronx, New York, 10468
| | - Shaneen M Singh
- Department of Biology, The Graduate Center of the City University of New YorkNew York, New York, 10016
- Department of Biology, Brooklyn College, The City University of New YorkBrooklyn, New York, 11210
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8
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Structural and biochemical characterization of the interaction between LGN and Frmpd1. J Mol Biol 2013; 425:1039-49. [PMID: 23318951 DOI: 10.1016/j.jmb.2013.01.003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2012] [Revised: 12/28/2012] [Accepted: 01/07/2013] [Indexed: 11/21/2022]
Abstract
The tetratricopeptide repeat (TPR) motif-containing protein LGN binds multiple targets and regulates their subcellular localizations and functions during both asymmetric and symmetric cell divisions. Here, we characterized the interaction between LGN-TPR motifs and FERM and PDZ domain containing 1 (Frmpd1) and reported the crystal structure of the complex at 2.4Å resolution. A highly conserved fragment at the center of Frmpd1 of ~20 residues was found to be necessary and sufficient to bind to LGN-TPR. This Frmpd1 fragment forms an extended structure and runs along the concave channel of the TPR superhelix in an antiparallel manner in the complex. Structural comparisons and biochemical studies of LGN/Frmpd1 and other known LGN/target interactions demonstrate that the LGN-TPR motifs are versatile and capable of recognizing multiple targets via diverse binding modes. Nevertheless, a conserved "E/QxEx4-5E/D/Qx1-2K/R" motif in LGN/Pins (partner of inscuteable) TPR binding proteins has been identified.
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9
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Lees JPB, Manlandro CM, Picton LK, Tan AZE, Casares S, Flanagan JM, Fleming KG, Hill RB. A designed point mutant in Fis1 disrupts dimerization and mitochondrial fission. J Mol Biol 2012; 423:143-58. [PMID: 22789569 DOI: 10.1016/j.jmb.2012.06.042] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2012] [Revised: 06/21/2012] [Accepted: 06/24/2012] [Indexed: 01/06/2023]
Abstract
Mitochondrial and peroxisomal fission are essential processes with defects resulting in cardiomyopathy and neonatal lethality. Central to organelle fission is Fis1, a monomeric tetratricopeptide repeat (TPR)-like protein whose role in assembly of the fission machinery remains obscure. Two nonfunctional, Saccharomyces cerevisiae Fis1 mutants (L80P or E78D/I85T/Y88H) were previously identified in genetic screens. Here, we find that these two variants in the cytosolic domain of Fis1 (Fis1ΔTM) are unexpectedly dimeric. A truncation variant of Fis1ΔTM that lacks an N-terminal regulatory domain is also found to be dimeric. The ability to dimerize is a property innate to the native Fis1ΔTM amino acid sequence as we find this domain is dimeric after transient exposure to elevated temperature or chemical denaturants and is kinetically trapped at room temperature. This is the first demonstration of a specific self-association in solution for the Fis1 cytoplasmic domain. We propose a three-dimensional domain-swapped model for dimerization that is validated by a designed mutation, A72P, which potently disrupts dimerization of wild-type Fis1. A72P also disrupts dimerization of nonfunctional variants, indicating a common structural basis for dimerization. The obligate monomer variant A72P, like the dimer-promoting variants, is nonfunctional in fission, consistent with a model in which Fis1 activity depends on its ability to interconvert between monomer and dimer species. These studies suggest a new functionally important manner in which TPR-containing proteins may reversibly self-associate.
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Affiliation(s)
- Jonathan P B Lees
- Department of Biology, Johns Hopkins University, Baltimore, MD 21218, USA
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10
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Park JH, Lee SY, Kim WY, Jung YJ, Chae HB, Jung HS, Kang CH, Shin MR, Kim SY, Su'udi M, Yun DJ, Lee KO, Kim MG, Lee SY. Heat-induced chaperone activity of serine/threonine protein phosphatase 5 enhances thermotolerance in Arabidopsis thaliana. THE NEW PHYTOLOGIST 2011; 191:692-705. [PMID: 21564098 DOI: 10.1111/j.1469-8137.2011.03734.x] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
• This study reports that Arabidopsis thaliana protein serine/threonine phosphatase 5 (AtPP5) plays a pivotal role in heat stress resistance. A high-molecular-weight (HMW) form of AtPP5 was isolated from heat-treated A. thaliana suspension cells. AtPP5 performs multiple functions, acting as a protein phosphatase, foldase chaperone, and holdase chaperone. The enzymatic activities of this versatile protein are closely associated with its oligomeric status, ranging from low oligomeric protein species to HMW complexes. • The phosphatase and foldase chaperone functions of AtPP5 are associated primarily with the low-molecular-weight (LMW) form, whereas the HMW form exhibits holdase chaperone activity. Transgenic over-expression of AtPP5 conferred enhanced heat shock resistance to wild-type A. thaliana and a T-DNA insertion knock-out mutant was defective in acquired thermotolerance. A recombinant phosphatase mutant (H290N) showed markedly increased holdase chaperone activity. • In addition, enhanced thermotolerance was observed in transgenic plants over-expressing H290N, which suggests that the holdase chaperone activity of AtPP5 is primarily responsible for AtPP5-mediated thermotolerance. • Collectively, the results from this study provide the first evidence that AtPP5 performs multiple enzymatic activities that are mediated by conformational changes induced by heat-shock stress.
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Affiliation(s)
- Jin Ho Park
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Sun Yong Lee
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Woe Yeon Kim
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Young Jun Jung
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Ho Byoung Chae
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Hyun Suk Jung
- Division of Electron Microscopic Research, Korea Basic Science Institute, 52 Eoeun-dong, Daejeon 305-333, Korea
| | - Chang Ho Kang
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Mi Rim Shin
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Sun Young Kim
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Mukhamad Su'udi
- National Academy of Agricultural Science, RDA, Suwon 441-856, Korea
| | - Dae Jin Yun
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Kyun Oh Lee
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
| | - Min Gab Kim
- National Academy of Agricultural Science, RDA, Suwon 441-856, Korea
| | - Sang Yeol Lee
- Division of Applied Life Science, Gyeongsang National University, Jinju 660-701, Korea
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11
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Allan RK, Ratajczak T. Versatile TPR domains accommodate different modes of target protein recognition and function. Cell Stress Chaperones 2011; 16:353-67. [PMID: 21153002 PMCID: PMC3118826 DOI: 10.1007/s12192-010-0248-0] [Citation(s) in RCA: 175] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 11/21/2010] [Accepted: 11/24/2010] [Indexed: 12/30/2022] Open
Abstract
The tetratricopeptide repeat (TPR) motif is one of many repeat motifs that form structural domains in proteins that can act as interaction scaffolds in the formation of multi-protein complexes involved in numerous cellular processes such as transcription, the cell cycle, protein translocation, protein degradation and host defence against invading pathogens. The crystal structures of many TPR domain-containing proteins have been determined, showing TPR motifs as two anti-parallel α-helices packed in tandem arrays to form a structure with an amphipathic groove which can bind a target peptide. This is however not the only mode of target recognition by TPR domains, with short amino acid insertions and alternative TPR motif conformations also shown to contribute to protein interactions, highlighting diversity in TPR domains and the versatility of this structure in mediating biological events.
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Affiliation(s)
- Rudi Kenneth Allan
- Centre for Medical Research, The University of Western Australia, Nedlands, WA 6009 Australia
- The Department of Endocrinology & Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, WA 6009 Australia
| | - Thomas Ratajczak
- Centre for Medical Research, The University of Western Australia, Nedlands, WA 6009 Australia
- The Department of Endocrinology & Diabetes, Sir Charles Gairdner Hospital, Hospital Avenue, Nedlands, WA 6009 Australia
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12
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Galland N, Michels PAM. Comparison of the peroxisomal matrix protein import system of different organisms. Exploration of possibilities for developing inhibitors of the import system of trypanosomatids for anti-parasite chemotherapy. Eur J Cell Biol 2010; 89:621-37. [PMID: 20435370 DOI: 10.1016/j.ejcb.2010.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2010] [Revised: 03/28/2010] [Accepted: 04/06/2010] [Indexed: 10/19/2022] Open
Abstract
In recent decades, research on peroxisome biogenesis has been particularly boosted since the role of these organelles in metabolism became unraveled. Indeed in plants, yeasts and fungi, peroxisomes play an important role in the adaptation of metabolism during developmental processes and/or altered environmental conditions. In mammals their importance is illustrated by the fact that several severe human inherited diseases have been identified as peroxisome biogenesis disorders (PBD). Particularly interesting are the glycosomes - peroxisome-like organelles in trypanosomatids where the major part of the glycolytic pathway is sequestered - because it was demonstrated that proper compartmentalization of matrix proteins inside glycosomes is essential for the parasite. Although the overall process of peroxisome biogenesis seems well conserved between species, careful study of the literature reveals nonetheless many differences at various steps. In this review, we present a comparison of the first two steps of peroxisome biogenesis - receptor loading and docking at the peroxisomal membrane - in yeasts, mammals, plants and trypanosomatids and highlight major differences in the import process between species despite the conservation of (some of) the proteins involved. Some of the unique features of the process as it occurs in trypanosomatids will be discussed with regard to the possibilities for exploiting them for the development of compounds that could specifically disturb interactions between trypanosomatid peroxins. This strategy could eventually lead to the discovery of drugs against the diseases caused by these parasites.
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Affiliation(s)
- Nathalie Galland
- Research Unit for Tropical Diseases, de Duve Institute, Brussels, Belgium
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13
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Wolf J, Schliebs W, Erdmann R. Peroxisomes as dynamic organelles: peroxisomal matrix protein import. FEBS J 2010; 277:3268-78. [PMID: 20629744 DOI: 10.1111/j.1742-4658.2010.07739.x] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The heterogeneity of peroxisomal matrix proteins which are imported in a folded, even oligomeric state, requires adaptive and dynamic properties of the translocation machinery. Dynamic multicompartmental subcellular distribution of peroxisomal proteins is governed by the accessibility of targeting signals. Conformational changes of peroxisomal targeting receptors upon cargo-binding might serve as a docking 'quality control'. Although the mechanisms are not understood in detail, recent work suggests the existence of a transient translocon within the peroxisomal membrane. Rapid formation and disassembly of the transient import pore ensures the integrity of the peroxisomal membrane barrier for small metabolites. In this review, we will focus on the regulatory aspects of peroxisomal matrix protein import.
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Affiliation(s)
- Janina Wolf
- Institut für Physiologische Chemie, Medizinische Fakultät, Ruhr-Universität Bochum, Bochum, Germany
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14
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Hartley JL, Zachos NC, Dawood B, Donowitz M, Forman J, Pollitt RJ, Morgan NV, Tee L, Gissen P, Kahr WHA, Knisely AS, Watson S, Chitayat D, Booth IW, Protheroe S, Murphy S, de Vries E, Kelly DA, Maher ER. Mutations in TTC37 cause trichohepatoenteric syndrome (phenotypic diarrhea of infancy). Gastroenterology 2010; 138:2388-98, 2398.e1-2. [PMID: 20176027 PMCID: PMC3166659 DOI: 10.1053/j.gastro.2010.02.010] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/22/2009] [Revised: 01/31/2010] [Accepted: 02/09/2010] [Indexed: 01/29/2023]
Abstract
BACKGROUND & AIMS Trichohepatoenteric syndrome (THES) is an autosomal-recessive disorder characterized by life-threatening diarrhea in infancy, immunodeficiency, liver disease, trichorrhexis nodosa, facial dysmorphism, hypopigmentation, and cardiac defects. We attempted to characterize the phenotype and elucidate the molecular basis of THES. METHODS Twelve patients with classic THES from 11 families had detailed phenotyping. Autozygosity mapping was undertaken in 8 patients from consanguineous families using 250,000 single nucleotide polymorphism arrays and linked regions evaluated using microsatellite markers. Linkage was confirmed to one region from which candidate genes were analyzed. The effect of mutations on protein production and/or localization in hepatocytes and intestinal epithelial cells from affected patients was characterized by immunohistochemistry. RESULTS Previously unrecognized platelet abnormalities (reduced platelet alpha-granules, unusual stimulated alpha granule content release, abnormal lipid inclusions, abnormal platelet canalicular system, and reduced number of microtubules) were identified. The THES locus was mapped to 5q14.3-5q21.2. Sequencing of candidate genes showed mutations in TTC37, which encodes the uncharacterized tetratricopeptide repeat protein, thespin. Bioinformatic analysis suggested thespin to be involved in protein-protein interactions or chaperone. Preliminary studies of enterocyte brush-border ion transporter proteins (sodium hydrogen exchanger 2, sodium hydrogen exchanger 3, aquaporin 7, sodium iodide symporter, and hydrogen potassium adenosine triphosphatase [ATPase]) showed reduced expression or mislocalization in all THES patients with different profiles for each. In contrast the basolateral localization of Na/K ATPase was not altered. CONCLUSIONS THES is caused by mutations in TTC37. TTC37 mutations have a multisystem effect, which may be owing to abnormal stability and/or intracellular localization of TTC37 target proteins.
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Affiliation(s)
- Jane Louise Hartley
- Department of Medical and Molecular Genetics, School of Clinical and Experimental Medicine, University of Birmingham College of Medical and Dental School, Institute of Biomedical Research, Edgbaston, Birmingham, UK.
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15
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Shiozawa K, Konarev PV, Neufeld C, Wilmanns M, Svergun DI. Solution structure of human Pex5.Pex14.PTS1 protein complexes obtained by small angle X-ray scattering. J Biol Chem 2009; 284:25334-42. [PMID: 19584060 DOI: 10.1074/jbc.m109.002311] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The Pex5p receptor recognizes newly synthesized peroxisomal matrix proteins which have a C-terminal peroxisomal targeting signal to the peroxisome. After docking to protein complexes on the membrane, these proteins are translocated across the membrane. The docking mechanism remains unclear, as no structural data on the multicomponent docking complex are available. As the interaction of the cargo-loaded Pex5p receptor and the peroxisomal membrane protein Pex14p is the essential primary docking step, we have investigated the solution structure of these complexes by small angle x-ray scattering and static light scattering. Titration studies yielded a 1:6 stoichiometry for the Pex5p.Pex14p complex, and low resolution structural models were reconstructed from the x-ray scattering data. The free full-length human Pex5p is monomeric in solution, with an elongated, partially unfolded N-terminal domain. The model of the complex reveals that the N terminus of Pex5p remains extended in the presence of cargo and Pex14p, the latter proteins being significantly intermingled with the Pex5p moiety. These results suggest that the extended structure of Pex5p may play a role in interactions with other substrates such as lipids and membrane proteins during the formation of functional multiprotein complexes.
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Affiliation(s)
- Kumiko Shiozawa
- European Molecular Biology Laboratory-Hamburg Outstation, c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany
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16
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Evolutionarily evolved discriminators in the 3-TPR domain of the Toc64 family involved in protein translocation at the outer membrane of chloroplasts and mitochondria. J Mol Model 2009; 15:971-82. [DOI: 10.1007/s00894-008-0449-y] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2008] [Accepted: 12/16/2008] [Indexed: 10/21/2022]
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17
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Structural insights into the recognition of peroxisomal targeting signal 1 by Trypanosoma brucei peroxin 5. J Mol Biol 2008; 381:867-80. [PMID: 18598704 DOI: 10.1016/j.jmb.2008.05.089] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2008] [Revised: 05/29/2008] [Accepted: 05/31/2008] [Indexed: 11/24/2022]
Abstract
Glycosomes are peroxisome-like organelles essential for trypanosomatid parasites. Glycosome biogenesis is mediated by proteins called "peroxins," which are considered to be promising drug targets in pathogenic Trypanosomatidae. The first step during protein translocation across the glycosomal membrane of peroxisomal targeting signal 1 (PTS1)-harboring proteins is signal recognition by the cytosolic receptor peroxin 5 (PEX5). The C-terminal PTS1 motifs interact with the PTS1 binding domain (P1BD) of PEX5, which is made up of seven tetratricopeptide repeats. Obtaining diffraction-quality crystals of the P1BD of Trypanosoma brucei PEX5 (TbPEX5) required surface entropy reduction mutagenesis. Each of the seven tetratricopeptide repeats appears to have a residue in the alpha(L) conformation in the loop connecting helices A and B. Five crystal structures of the P1BD of TbPEX5 were determined, each in complex with a hepta- or decapeptide corresponding to a natural or nonnatural PTS1 sequence. The PTS1 peptides are bound between the two subdomains of the P1BD. These structures indicate precise recognition of the C-terminal Leu of the PTS1 motif and important interactions between the PTS1 peptide main chain and up to five invariant Asn side chains of PEX5. The TbPEX5 structures reported here reveal a unique hydrophobic pocket in the subdomain interface that might be explored to obtain compounds that prevent relative motions of the subdomains and interfere selectively with PTS1 motif binding or release in trypanosomatids, and would therefore disrupt glycosome biogenesis and prevent parasite growth.
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18
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McCleverty CJ, Columbus L, Kreusch A, Lesley SA. Structure and ligand binding of the soluble domain of a Thermotoga maritima membrane protein of unknown function TM1634. Protein Sci 2008; 17:869-77. [PMID: 18369189 DOI: 10.1110/ps.083432208] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
As a part of the Joint Center for Structural Genomics (JCSG) biological targets, the structures of soluble domains of membrane proteins from Thermotoga maritima were pursued. Here, we report the crystal structure of the soluble domain of TM1634, a putative membrane protein of 128 residues (15.1 kDa) and unknown function. The soluble domain of TM1634 is an alpha-helical dimer that contains a single tetratrico peptide repeat (TPR) motif in each monomer where each motif is similar to that found in Tom20. The overall fold, however, is unique and a DALI search does not identify similar folds beyond the 38-residue TPR motif. Two different putative ligand binding sites, in which PEG200 and Co(2+) were located, were identified using crystallography and NMR, respectively.
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Affiliation(s)
- Clare J McCleverty
- The Genomics Institute of the Novartis Research Foundation, San Diego, California 92121, USA
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19
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Han D, Kim K, Oh J, Park J, Kim Y. TPR domain of NrfG mediates complex formation between heme lyase and formate‐dependent nitrite reductase in
Escherichia coli
O157:H7. Proteins 2008; 70:900-14. [PMID: 17803240 DOI: 10.1002/prot.21597] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Escherichia coli synthesize C-type cytochromes only during anaerobic growth in media supplemented with nitrate and nitrite. The reduction of nitrate to ammonium in the periplasm of Escherichia coli involves two separate periplasmic enzymes, nitrate reductase and nitrite reductase. The nitrite reductase involved, NrfA, contains cytochrome C and is synthesized coordinately with a membrane-associated cytochrome C, NrfB, during growth in the presence of nitrite or in limiting nitrate concentrations. The genes NrfE, NrfF, and NrfG are required for the formate-dependent nitrite reduction pathway, which involves at least two C-type cytochrome proteins, NrfA and NrfB. The NrfE, NrfF, and NrfG genes (heme lyase complex) are involved in the maturation of a special C-type cytochrome, apocytochrome C (apoNrfA), to cytochrome C (NrfA) by transferring a heme to the unusual heme binding motif of the Cys-Trp-Ser-Cys-Lys sequence in apoNrfA protein. Thus, in order to further investigate the roles of NrfG in the formation of heme lyase complex (NrfEFG) and in the interaction between heme lyase complex and formate-dependent nitrite reductase (NrfA), we determined the crystal structure of NrfG at 2.05 A. The structure of NrfG showed that the contact between heme lyase complex (NrfEFG) and NrfA is accomplished via a TPR domain in NrfG which serves as a binding site for the C-terminal motif of NrfA. The portion of NrfA that binds to TPR domain of NrfG has a unique secondary motif, a helix followed by about a six-residue C-terminal loop (the so called "hook conformation"). This study allows us to better understand the mechanism of special C-type cytochrome assembly during the maturation of formate-dependent nitrite reductase, and also adds a new TPR binding conformation to the list of TPR-mediated protein-protein interactions.
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Affiliation(s)
- Dohyun Han
- College of Medicine, Seoul National University, Yongon-Dong, Seoul 110-799, Korea
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20
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Stanley WA, Fodor K, Marti-Renom MA, Schliebs W, Wilmanns M. Protein translocation into peroxisomes by ring-shaped import receptors. FEBS Lett 2007; 581:4795-802. [PMID: 17884042 DOI: 10.1016/j.febslet.2007.09.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2007] [Accepted: 09/04/2007] [Indexed: 12/27/2022]
Abstract
Folded and functional proteins destined for translocation from the cytosol into the peroxisomal matrix are recognized by two different peroxisomal import receptors, Pex5p and Pex7p. Both cargo-loaded receptors dock on the same translocon components, followed by cargo release and receptor recycling, as part of the complete translocation process. Recent structural and functional evidence on the Pex5p receptor has provided insight on the molecular requirements of specific cargo recognition, while the remaining processes still remain largely elusive. Comparison of experimental structures of Pex5p and a structural model of Pex7p reveal that both receptors are built by ring-like arrangements with cargo binding sites, central to the respective structures. Although, molecular insight into the complete peroxisomal translocon still remains to be determined, emerging data allow to deduce common molecular principles that may hold for other translocation systems as well.
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Affiliation(s)
- Will A Stanley
- ARC Plant Energy Biology Centre M316, University of Western Australia, 35 Stirling Highway, Crawley, WA 6009, Australia
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21
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Stanley WA, Wilmanns M. Dynamic architecture of the peroxisomal import receptor Pex5p. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2006; 1763:1592-8. [PMID: 17141887 DOI: 10.1016/j.bbamcr.2006.10.015] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/13/2006] [Revised: 10/26/2006] [Accepted: 10/26/2006] [Indexed: 11/29/2022]
Abstract
The majority of peroxisomal matrix proteins are recognized by the import receptor Pex5p. The receptor is dynamic in terms of its overall architecture and association with the peroxisomal membrane. It participates in different protein complexes during the translocation of cargos from the cytosol to the peroxisomal matrix. Its sequence comprises two structurally and functionally autonomous parts. The N-terminal segment interacts with several peroxins that assemble into distinct protein complexes during cargo translocation. Despite evidence for alpha-helical binding motifs for some of these components (Pex13p, Pex14p) its overall appearance is that of a molten globule and folding/unfolding transitions may play a critical role in its function. In contrast, most of the C-terminal part of the receptor folds into a ring-like alpha-helical structure and binds folded and functionally intact peroxisomal targets that bear a C-terminal peroxisomal targeting signal type-1. Some of these targets also bind to secondary binding sites of the receptor.
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Affiliation(s)
- Will A Stanley
- EMBL-Hamburg Outstation, c/o DESY, Notkestrasse 85, 22603 Hamburg, Germany
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22
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Madrid K, Jardim A. Peroxin 5-peroxin 14 association in the protozoan Leishmania donovani involves a novel protein-protein interaction motif. Biochem J 2006; 391:105-14. [PMID: 15929724 PMCID: PMC1237144 DOI: 10.1042/bj20050328] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Import of proteins with a PTS1 (peroxisomal targeting signal 1) into the Leishmania glycosomal organelle involves docking of a PTS1-laden LdPEX5 [Leishmania donovani PEX5 (peroxin 5)] receptor to LdPEX14 on the surface of the glycosomal membrane. In higher eukaryotes, the PEX5-PEX14 interaction is mediated by a conserved diaromatic WXXXY/F motif. Site-directed and deletion mutageneses of the three WXXXY/F repeats in LdPEX5 did not abolish the LdPEX5-LdPEX14 association. Analysis of the equilibrium dissociation constant (K(d)) revealed that ldpex5-W53A (Trp53-->Ala), ldpex5-W293A, ldpex5-W176,293A and ldpex5-W53,176,293A mutant receptors were capable of binding LdPEX14 with affinities comparable with wild-type LdPEX5. That the diaromatic motifs were not required for the LdPEX5-LdPEX14 interaction was further verified by deletion analysis that showed that ldpex5 deletion mutants or ldpex5 fragments lacking the WXXXY/F motifs retained LdPEX14 binding activity. Mapping studies of LdPEX5 indicated that the necessary elements required for LdPEX14 association were localized to a region between residues 290 and 323. Finally, mutational analysis of LdPEX14 confirmed that residues 23-63, which encompass the conserved signature sequence AX2FLX7SPX6FLKGKGL/V present in all PEX14 proteins, are essential for LdPEX5 binding.
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Affiliation(s)
- Kleber P. Madrid
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
| | - Armando Jardim
- Institute of Parasitology, McGill University, Macdonald Campus, Ste. Anne de Bellevue, Quebec, Canada H9X 3V9
- To whom correspondence should be addressed (email )
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23
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Edqvist PJ, Bröms JE, Betts HJ, Forsberg A, Pallen MJ, Francis MS. Tetratricopeptide repeats in the type III secretion chaperone, LcrH: their role in substrate binding and secretion. Mol Microbiol 2006; 59:31-44. [PMID: 16359316 DOI: 10.1111/j.1365-2958.2005.04923.x] [Citation(s) in RCA: 57] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Non-flagellar type III secretion systems (T3SSs) transport proteins across the bacterial cell and into eukaryotic cells. Targeting of proteins into host cells requires a dedicated translocation apparatus. Efficient secretion of the translocator proteins that make up this apparatus depends on molecular chaperones. Chaperones of the translocators (also called class-II chaperones) are characterized by the possession of three tandem tetratricopeptide repeats (TPRs). We wished to dissect the relations between chaperone structure and function and to validate a structural model using site-directed mutagenesis. Drawing on a number of experimental approaches and focusing on LcrH, a class-II chaperone from the Yersinia Ysc-Yop T3SS, we examined the contributions of different residues, residue classes and regions of the protein to chaperone stability, chaperone-substrate binding, substrate stability and secretion and regulation of Yop protein synthesis. We confirmed the expected role of the conserved canonical residues from the TPRs to chaperone stability and function. Eleven mutations specifically abrogated YopB binding or secretion while three mutations led to a specific loss of YopD secretion. These are the first mutations described for any class-II chaperone that allow interactions with one translocator to be dissociated from interactions with the other. Strikingly, all mutations affecting the interaction with YopB mapped to residues with side chains projecting from the inner, concave surface of the modelled TPR structure, defining a YopB interaction site. Conversely, all mutations preventing YopD secretion affect residues that lie on the outer, convex surface of the triple-TPR cluster in our model, suggesting that this region of the molecule represents a distinct interaction site for YopD. Intriguingly, one of the LcrH double mutants, Y40A/F44A, was able to maintain stable substrates inside bacteria, but unable to secrete them, suggesting that these two residues might influence delivery of substrates to the secretion apparatus.
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Affiliation(s)
- Petra J Edqvist
- Department of Molecular Biology, Umeå University, SE-901 87 Umeå, Sweden
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24
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Krazy H, Michels PAM. Identification and characterization of three peroxins--PEX6, PEX10 and PEX12--involved in glycosome biogenesis in Trypanosoma brucei. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2005; 1763:6-17. [PMID: 16388862 DOI: 10.1016/j.bbamcr.2005.11.002] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2005] [Revised: 11/05/2005] [Accepted: 11/07/2005] [Indexed: 12/14/2022]
Abstract
Protozoan Kinetoplastida such as the pathogenic trypanosomes compartmentalize several important metabolic systems, including the glycolytic pathway, in peroxisome-like organelles designated glycosomes. Genes for three proteins involved in glycosome biogenesis of Trypanosoma brucei were identified. A preliminary analysis of these proteins, the peroxins PEX6, PEX10 and PEX12, was performed. Cellular depletion of these peroxins by RNA interference affected growth of both mammalian bloodstream-form and insect-form (procyclic) trypanosomes. The bloodstream forms, which rely entirely on glycolysis for their ATP supply, were more rapidly killed. Both by immunofluorescence studies of intact procyclic T. brucei cells and subcellular fractionation experiments involving differential permeabilization of plasma and organellar membranes it was shown that RNAi-dependent knockdown of the expression of each of these peroxins resulted in the partial mis-localization of different types of glycosomal matrix enzymes to the cytoplasm: proteins with consensus motifs such as the C-terminal type 1 peroxisomal targeting signal PTS1 or the N-terminal signal PTS2 and a protein for which the sorting information is present in a polypeptide-internal fragment not containing an identifiable consensus sequence.
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Affiliation(s)
- Hanane Krazy
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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25
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Kim J, Sitaraman S, Hierro A, Beach BM, Odorizzi G, Hurley JH. Structural basis for endosomal targeting by the Bro1 domain. Dev Cell 2005; 8:937-47. [PMID: 15935782 PMCID: PMC2862258 DOI: 10.1016/j.devcel.2005.04.001] [Citation(s) in RCA: 160] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2005] [Revised: 04/08/2005] [Accepted: 04/12/2005] [Indexed: 01/16/2023]
Abstract
Proteins delivered to the lysosome or the yeast vacuole via late endosomes are sorted by the ESCRT complexes and by associated proteins, including Alix and its yeast homolog Bro1. Alix, Bro1, and several other late endosomal proteins share a conserved 160 residue Bro1 domain whose boundaries, structure, and function have not been characterized. The crystal structure of the Bro1 domain of Bro1 reveals a folded core of 367 residues. The extended Bro1 domain is necessary and sufficient for binding to the ESCRT-III subunit Snf7 and for the recruitment of Bro1 to late endosomes. The structure resembles a boomerang with its concave face filled in and contains a triple tetratricopeptide repeat domain as a substructure. Snf7 binds to a conserved hydrophobic patch on Bro1 that is required for protein complex formation and for the protein-sorting function of Bro1. These results define a conserved mechanism whereby Bro1 domain-containing proteins are targeted to endosomes by Snf7 and its orthologs.
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Affiliation(s)
- Jaewon Kim
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892
| | - Sujatha Sitaraman
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - Aitor Hierro
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892
| | - Bridgette M. Beach
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892
| | - Greg Odorizzi
- Department of Molecular, Cellular, and Developmental Biology, University of Colorado, Boulder, Colorado 80309
| | - James H. Hurley
- Laboratory of Molecular Biology, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, U.S. Department of Health and Human Services, Bethesda, Maryland 20892
- Correspondence:
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26
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Abstract
The molecular chaperone machinery contains multiple protein components that have 1 or more structural domains composed of tetratricopeptide repeat (TPR) motifs. Many other proteins of separate or unknown function also have TPR domains, so this motif is not exclusive to molecular chaperones. A general function of TPR domains is to bind other polypeptides, but this otherwise prosaic function has been exploited in an assortment of ways that link chaperones and other protein systems into cooperative networks. Among the best-characterized TPR proteins are several cochaperones that participate in assembly and regulation of steroid receptor complexes. Steroid receptors, members of the nuclear receptor subfamily, are hormone-dependent transcription factors that regulate many vertebrate pathways of homeostasis, growth, differentiation, reproduction, and pathology and, as such, have been of great interest to biologists and clinicians. Moreover, the steroid receptors are among the first recognized native clients for chaperones and have been widely studied models for complex chaperone interactions. To provide a coherent, representative minireview of TPR protein function, the scope of this article has been narrowed down primarily to functions of steroid receptor-associated TPR cochaperones.
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Affiliation(s)
- David F Smith
- S.C. Johnson Research Center, Mayo Clinic Scottsdale, Scottsdale, AZ 85259, USA.
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27
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Wilson CGM, Kajander T, Regan L. The crystal structure of NlpI. A prokaryotic tetratricopeptide repeat protein with a globular fold. FEBS J 2005; 272:166-79. [PMID: 15634341 DOI: 10.1111/j.1432-1033.2004.04397.x] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
There are several different families of repeat proteins. In each, a distinct structural motif is repeated in tandem to generate an elongated structure. The nonglobular, extended structures that result are particularly well suited to present a large surface area and to function as interaction domains. Many repeat proteins have been demonstrated experimentally to fold and function as independent domains. In tetratricopeptide (TPR) repeats, the repeat unit is a helix-turn-helix motif. The majority of TPR motifs occur as three to over 12 tandem repeats in different proteins. The majority of TPR structures in the Protein Data Bank are of isolated domains. Here we present the high-resolution structure of NlpI, the first structure of a complete TPR-containing protein. We show that in this instance the TPR motifs do not fold and function as an independent domain, but are fully integrated into the three-dimensional structure of a globular protein. The NlpI structure is also the first TPR structure from a prokaryote. It is of particular interest because it is a membrane-associated protein, and mutations in it alter septation and virulence.
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Affiliation(s)
- Christopher G M Wilson
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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28
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Moyersoen J, Choe J, Fan E, Hol WGJ, Michels PAM. Biogenesis of peroxisomes and glycosomes: trypanosomatid glycosome assembly is a promising new drug target. FEMS Microbiol Rev 2005; 28:603-43. [PMID: 15539076 DOI: 10.1016/j.femsre.2004.06.004] [Citation(s) in RCA: 75] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2004] [Revised: 06/14/2004] [Accepted: 06/15/2004] [Indexed: 10/26/2022] Open
Abstract
In trypanosomatids (Trypanosoma and Leishmania), protozoa responsible for serious diseases of mankind in tropical and subtropical countries, core carbohydrate metabolism including glycolysis is compartmentalized in peculiar peroxisomes called glycosomes. Proper biogenesis of these organelles and the correct sequestering of glycolytic enzymes are essential to these parasites. Biogenesis of glycosomes in trypanosomatids and that of peroxisomes in other eukaryotes, including the human host, occur via homologous processes involving proteins called peroxins, which exert their function through multiple, transient interactions with each other. Decreased expression of peroxins leads to death of trypanosomes. Peroxins show only a low level of sequence conservation. Therefore, it seems feasible to design compounds that will prevent interactions of proteins involved in biogenesis of trypanosomatid glycosomes without interfering with peroxisome formation in the human host cells. Such compounds would be suitable as lead drugs against trypanosomatid-borne diseases.
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Affiliation(s)
- Juliette Moyersoen
- Research Unit for Tropical Diseases, Christian de Duve Institute of Cellular Pathology and Laboratory of Biochemistry, Université Catholique de Louvain, ICP-TROP 74.39, Avenue Hippocrate 74, B-1200 Brussels, Belgium
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29
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Jínek M, Rehwinkel J, Lazarus BD, Izaurralde E, Hanover JA, Conti E. The superhelical TPR-repeat domain of O-linked GlcNAc transferase exhibits structural similarities to importin alpha. Nat Struct Mol Biol 2004; 11:1001-7. [PMID: 15361863 DOI: 10.1038/nsmb833] [Citation(s) in RCA: 224] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2004] [Accepted: 07/20/2004] [Indexed: 11/08/2022]
Abstract
Addition of N-acetylglucosamine (GlcNAc) is a ubiquitous form of intracellular glycosylation catalyzed by the conserved O-linked GlcNAc transferase (OGT). OGT contains an N-terminal domain of tetratricopeptide (TPR) repeats that mediates the recognition of a broad range of target proteins. Components of the nuclear pore complex are major OGT targets, as OGT depletion by RNA interference (RNAi) results in the loss of GlcNAc modification at the nuclear envelope. To gain insight into the mechanism of target recognition, we solved the crystal structure of the homodimeric TPR domain of human OGT, which contains 11.5 TPR repeats. The repeats form an elongated superhelix. The concave surface of the superhelix is lined by absolutely conserved asparagines, in a manner reminiscent of the peptide-binding site of importin alpha. Based on this structural similarity, we propose that OGT uses an analogous molecular mechanism to recognize its targets.
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Affiliation(s)
- Martin Jínek
- Structural and Computational Biology, European Molecular Biology Laboratory, Meyerhofstrasse 1, D-69117 Heidelberg, Germany
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Madrid KP, De Crescenzo G, Wang S, Jardim A. Modulation of the Leishmania donovani peroxin 5 quaternary structure by peroxisomal targeting signal 1 ligands. Mol Cell Biol 2004; 24:7331-44. [PMID: 15314146 PMCID: PMC506994 DOI: 10.1128/mcb.24.17.7331-7344.2004] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2004] [Revised: 04/28/2004] [Accepted: 06/03/2004] [Indexed: 11/20/2022] Open
Abstract
The import of proteins containing the peroxisomal targeting signal 1 (PTS1) into the Leishmania glycosome is dependent on the docking of the PTS1-loaded LdPEX5 cytosolic receptor with LdPEX14 on the glycosome surface. Here we show that, in the absence of PTS1, LdPEX5 is a tetramer that is stabilized by two distinct interaction domains; the first is a coiled-coil motif encompassing residues 277 to 310, whereas the second domain is localized to residues 1 to 202. By using microcalorimetry, surface plasmon resonance, and size exclusion chromatography techniques, we show that PTS1 peptide binding to LdPEX5 tetramers promotes their dissociation into dimeric structures, which are stabilized by a coiled-coil interaction. Moreover, we demonstrated that the resulting LdPEX5-PTS1 complex is remarkably stable and exhibits extremely slow dissociation kinetics. However, binding of LdPEX14 to LdPEX5 modulates the LdPEX5-PTS1 affinity as it decreases the thermodynamic dissociation constant for this latter complex by 10-fold. These changes in the oligomeric state of LdPEX5 and in its affinity for PTS1 ligand upon LdPEX14 binding may explain how, under physiological conditions, LdPEX5 can function to deliver and unload its cargo to the protein translocation machinery on the glycosomal membrane.
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Affiliation(s)
- Kleber P Madrid
- Institute of Parasitology, McGill University, Montreal, Quebec, Canada
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31
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Moir RD, Willis IM. Tetratricopeptide repeats of Tfc4 and a limiting step in the assembly of the initiation factor TFIIIB. ADVANCES IN PROTEIN CHEMISTRY 2004; 67:93-121. [PMID: 14969725 DOI: 10.1016/s0065-3233(04)67004-5] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Affiliation(s)
- Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Cheung-Flynn J, Roberts PJ, Riggs DL, Smith DF. C-terminal sequences outside the tetratricopeptide repeat domain of FKBP51 and FKBP52 cause differential binding to Hsp90. J Biol Chem 2003; 278:17388-94. [PMID: 12611898 DOI: 10.1074/jbc.m300955200] [Citation(s) in RCA: 67] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Hsp90 assembles with steroid receptors and other client proteins in association with one or more Hsp90-binding cochaperones, some of which contain a common tetratricopeptide repeat (TPR) domain. Included in the TPR cochaperones are the Hsp70-Hsp90-organizing protein Hop, the FK506-binding immunophilins FKBP52 and FKBP51, the cyclosporin A-binding immunophilin CyP40, and protein phosphatase PP5. The TPR domains from these proteins have similar x-ray crystallographic structures and target cochaperone binding to the MEEVD sequence that terminates Hsp90. However, despite these similarities, the TPR cochaperones have distinctive properties for binding Hsp90 and assembling with Hsp90.steroid receptor complexes. To identify structural features that differentiate binding of FKBP51 and FKBP52 to Hsp90, we generated an assortment of truncation mutants and chimeras that were compared for coimmunoprecipitation with Hsp90. Although the core TPR domain (approximately amino acids 260-400) of FKBP51 and FKBP52 is required for Hsp90 binding, the C-terminal 60 amino acids (approximately 400-end) also influence Hsp90 binding. More specifically, we find that amino acids 400-420 play a critical role for Hsp90 binding by either FKBP. Within this 20-amino acid region, we have identified a consensus sequence motif that is also present in some other TPR cochaperones. Additionally, the final 30 amino acids of FKBP51 enhance binding to Hsp90, whereas the corresponding region of FKBP52 moderates binding to Hsp90. Taking into account the x-ray crystal structure for FKBP51, we conclude that the C-terminal regions of FKBP51 and FKBP52 outside the core TPR domains are likely to assume alternative conformations that significantly impact Hsp90 binding.
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Affiliation(s)
- Joyce Cheung-Flynn
- S C Johnson Research Center, Mayo Clinic Scottsdale, Scottsdale, Arizona 85259, USA
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33
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Main ERG, Xiong Y, Cocco MJ, D'Andrea L, Regan L. Design of stable alpha-helical arrays from an idealized TPR motif. Structure 2003; 11:497-508. [PMID: 12737816 DOI: 10.1016/s0969-2126(03)00076-5] [Citation(s) in RCA: 217] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The tetratricopeptide repeat (TPR) is a 34-amino acid alpha-helical motif that occurs in over 300 different proteins. In the different proteins, three to sixteen or more TPR motifs occur in tandem arrays and function to mediate protein-protein interactions. The binding specificity of each TPR protein is different, although the underlying structural motif is the same. Here we describe a statistical approach to the design of an idealized TPR motif. We present the high-resolution X-ray crystal structures (to 1.55 and 1.6 A) of designed TPR proteins and describe their solution properties and stability. A detailed analysis of these structures provides an understanding of the TPR motif, how it is repeated to give helical arrays with different superhelical twists, and how a very stable framework may be constructed for future functional designs.
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Affiliation(s)
- Ewan R G Main
- Department of Molecular Biophysics and Biochemistry, Yale University, New Haven, CT 06520, USA
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Zhu W, Rainville IR, Ding M, Bolus M, Heintz NH, Pederson DS. Evidence that the pre-mRNA splicing factor Clf1p plays a role in DNA replication in Saccharomyces cerevisiae. Genetics 2002; 160:1319-33. [PMID: 11973290 PMCID: PMC1462043 DOI: 10.1093/genetics/160.4.1319] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Clf1p is an essential, highly conserved protein in S. cerevisiae that has been implicated in pre-mRNA splicing. Clf1p's ortholog in Drosophila, Crn, is required for normal cell proliferation. Cells depleted of Clf1p arrest primarily with large buds, a single nucleus, a 2C DNA content, and a short, intact mitotic spindle. We isolated temperature-sensitive clf1 mutants that exhibit similar mitotic defects when released to the restrictive temperature from an early S-phase block. While these mutants also accumulate unspliced pre-mRNA at the restrictive temperature, the mitotic arrest does not appear to result from a failure to splice tubulin pre-mRNA. Moreover, the same mutants exhibit a delayed entry into S phase when released to the restrictive temperature from a G1 phase block. This delay could not be suppressed by disruption of the S-phase CDK inhibitor SIC1, suggesting that Clf1p is involved in DNA replication. Consistent with this possibility, we find that Clf1p (but not the mutant clf1p) interacts with the DNA replication initiation protein Orc2p in two-hybrid and co-immunoprecipitation assays, that Clf1p preferentially associates with origins of DNA replication, and that this association is Orc2p dependent. These observations suggest that Clf1p plays a direct role in the initiation of DNA replication.
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Affiliation(s)
- Wenge Zhu
- Department of Microbiology, University of Vermont, Burlington 05405-0068, USA
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35
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Velten M, Gomez-Vrielynck N, Chaffotte A, Ladjimi MM. Domain structure of the HSC70 cochaperone, HIP. J Biol Chem 2002; 277:259-66. [PMID: 11687574 DOI: 10.1074/jbc.m106881200] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The domain structure of the HSC70-interacting protein (HIP), a 43-kDa cytoplasmic cochaperone involved in the regulation of HSC70 chaperone activity and the maturation of progesterone receptor, has been probed by limited proteolysis and biophysical and biochemical approaches. HIP proteolysis by thrombin and chymotrypsin generates essentially two fragments, an NH2-terminal fragment of 25 kDa (N25) and a COOH-terminal fragment of 18 kDa (C18) that appear to be well folded and stable as indicated by circular dichroism and recombinant expression in Escherichia coli. NH2-terminal amino acid sequencing of the respective fragments indicates that both proteases cleave HIP within a predicted alpha-helix following the tetratricopeptide repeat (TPR) region, despite their different specificities and the presence of several potential cleavage sites scattered throughout the sequence, thus suggesting that this region is particularly accessible and may constitute a linker between two structural domains. After size exclusion chromatography, N25 and C18 elute as two distinct and homogeneous species having a Stokes radius of 49 and 24 A, respectively. Equilibrium sedimentation and sedimentation velocity indicate that N25 is a stable dimer, whereas C18 is monomeric in solution, with sedimentation coefficients of 3.2 and 2.3 S and f/f(o) values of 1.5 and 1.1 for N25 and C18, respectively, indicating that the N25 is elongated whereas C18 is globular in shape. Both domains are able to bind to the ATPase domain of HSC70 and inhibit rhodanese aggregation. Moreover, their effects appear to be additive when used in combination, suggesting a cooperation of these domains in the full-length protein not only for HSC70 binding but also for chaperone activity. Altogether, these results indicate that HIP is made of two structural and functional domains, an NH2-terminal 25-kDa domain, responsible for the dimerization and the overall asymmetry of the molecule, and a COOH-terminal 18-kDa globular domain, both involved in HSC70 and unfolded protein binding.
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Affiliation(s)
- Marion Velten
- Laboratoire de Biochimie des Signaux Régulateurs Cellulaires et Moléculaires, UMR 7631, CNRS-Université Pierre et Marie Curie, 96 Boulevard Raspail and Institut Pasteur, 28 rue du Dr. Roux, Paris, France
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Moir RD, Puglia KV, Willis IM. Autoinhibition of TFIIIB70 binding by the tetratricopeptide repeat-containing subunit of TFIIIC. J Biol Chem 2002; 277:694-701. [PMID: 11684692 DOI: 10.1074/jbc.m108924200] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
An important step in the assembly of RNA polymerase (pol) III transcription complexes on tRNA and 5 S genes is the interaction between the tetratricopeptide repeat (TPR)-containing subunit of TFIIIC (TFIIIC131) and the TFIIB-related subunit of TFIIIB (TFIIIB70/Brf1). A fragment of TFIIIC131 that contains the hydrophilic amino terminus and two TPR arrays, with five and four repeats, respectively (Nt-TPR9), is sufficient to support an interaction with TFIIIB70. Here we evaluate the contribution of each TPR array to TFIIIB70 binding. Both TPR arrays bind independently to TFIIIB70 with TPR6-9 having a 4-fold higher apparent affinity than TPR1-5. However, the TPR arrays are not sufficient for a high affinity interaction with TFIIIB70. The addition of amino-terminal sequences increases the affinity of TPR1-5 18-fold to create a high affinity TFIIIB70 binding site (Nt-TPR5, 44 +/- 6 nm). Although the Nt-TPR5 and TPR6-9 fragments are contained entirely within the Nt-TPR9 fragment, the affinity of the latter is significantly lower than either of these smaller fragments. The results demonstrate that the TFIIIB70 binding sites in TFIIIC131 are subject to autoinhibition. We propose that the binding of TFIIIB70 to these sites within the TFIIIC complex may proceed in an ordered fashion.
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Affiliation(s)
- Robyn D Moir
- Department of Biochemistry, Albert Einstein College of Medicine, Bronx, New York 10461, USA
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Suresh S, Bressi JC, Kennedy KJ, Verlinde CL, Gelb MH, Hol WG. Conformational changes in Leishmania mexicana glyceraldehyde-3-phosphate dehydrogenase induced by designed inhibitors. J Mol Biol 2001; 309:423-35. [PMID: 11371162 DOI: 10.1006/jmbi.2001.4588] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
The glycolytic enzymes of trypanosomes are attractive drug targets, since the blood-stream form of Trypanosoma brucei lacks a functional citric acid cycle and is dependent solely on glycolysis for its energy requirements. Glyceraldehyde-3-phosphate dehydrogenases (GAPDH) from the pathogenic trypanosomatids T. brucei, Trypanosoma cruzi and Leishmania mexicana are quite similar to each other, and yet have sufficient structural differences compared to the human enzyme to enable the structure-based design of compounds that selectively inhibit all three trypanosomatid enzymes but not the human homologue. Adenosine analogs with substitutions on N-6 of the adenine ring and on the 2' position of the ribose moiety were designed, synthesized and tested for inhibition. Two crystal structures of L. mexicana glyceraldehyde-3-phosphate dehydrogenase in complex with high-affinity inhibitors that also block parasite growth were solved at a resolution of 2.6 A and 3.0 A. The complexes crystallized in the same crystal form, with one and a half tetramers in the crystallographic asymmetric unit. There is clear electron density for the inhibitor in all six copies of the binding site in each of the two structures. The L. mexicana GAPDH subunit exhibits substantial structural plasticity upon binding the inhibitor. Movements of the protein backbone, in response to inhibitor binding, enlarge a cavity at the binding site to accommodate the inhibitor in a classic example of induced fit. The extensive hydrophobic interactions between the protein and the two substituents on the adenine scaffold of the inhibitor provide a plausible explanation for the high affinity of these inhibitors for trypanosomatid GAPDHs.
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Affiliation(s)
- S Suresh
- Departments of Biological Structure, Biomolecular Structure Center, Howard Hughes Medical Institute, Seattle, WA 98915, USA
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