1
|
Fernández-Guerra P, Birkler RID, Merinero B, Ugarte M, Gregersen N, Rodríguez-Pombo P, Bross P, Palmfeldt J. Selected reaction monitoring as an effective method for reliable quantification of disease-associated proteins in maple syrup urine disease. Mol Genet Genomic Med 2014; 2:383-92. [PMID: 25333063 PMCID: PMC4190873 DOI: 10.1002/mgg3.88] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2014] [Revised: 04/25/2014] [Accepted: 04/29/2014] [Indexed: 12/15/2022] Open
Abstract
Selected reaction monitoring (SRM) mass spectrometry can quantitatively measure proteins by specific targeting of peptide sequences, and allows the determination of multiple proteins in one single analysis. Here, we show the feasibility of simultaneous measurements of multiple proteins in mitochondria-enriched samples from cultured fibroblasts from healthy individuals and patients with mutations in branched-chain α-ketoacid dehydrogenase (BCKDH) complex. BCKDH is a mitochondrial multienzyme complex and its defective activity causes maple syrup urine disease (MSUD), a rare but severe inherited metabolic disorder. Four different genes encode the catalytic subunits of BCKDH: E1α (BCKDHA), E1β (BCKDHB), E2 (DBT), and E3 (DLD). All four proteins were successfully quantified in healthy individuals. However, the E1α and E1β proteins were not detected in patients carrying mutations in one of those genes, whereas mRNA levels were almost unaltered, indicating instability of E1α and E1β monomers. Using SRM we elucidated the protein effects of mutations generating premature termination codons or misfolded proteins. SRM is a complement to transcript level measurements and a valuable tool to shed light on molecular mechanisms and on effects of pharmacological therapies at protein level. SRM is particularly effective for inherited disorders caused by multiple proteins such as defects in multienzyme complexes.
Collapse
Affiliation(s)
- Paula Fernández-Guerra
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark
| | - Rune I D Birkler
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark
| | - Begoña Merinero
- Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), Centro de Investigación en Red de Enfermedades Raras (CIBERER), IDIPAZ, Universidad Autónoma Madrid Madrid, Spain
| | - Magdalena Ugarte
- Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), Centro de Investigación en Red de Enfermedades Raras (CIBERER), IDIPAZ, Universidad Autónoma Madrid Madrid, Spain
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark
| | - Pilar Rodríguez-Pombo
- Dpto Biol. Mol., Centro de Diagnóstico de Enfermedades Moleculares (CEDEM), Centro de Biología Molecular Severo Ochoa, UAM-CSIC, Centro de Investigación en Red de Enfermedades Raras (CIBERER), IDIPAZ, Universidad Autónoma Madrid Madrid, Spain
| | - Peter Bross
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital Aarhus, Denmark
| |
Collapse
|
2
|
Jurkowski W, Kułaga T, Roterman I. Geometric parameters defining the structure of proteins--relation to early-stage folding step. J Biomol Struct Dyn 2011; 29:79-104. [PMID: 21696227 DOI: 10.1080/07391102.2011.10507376] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Two geometrical parameters describing the structure of a polypeptide: V-dihedral angle between two sequential peptide bond planes and R-radius of curvature are used for structural classification of polypeptide structure in proteins. The relation between these two parameters was the basis for the definition of the conformational sub-space for early-stage structural forms. The cluster analysis of V and lnR, applied to the selected proteins of well-defined secondary structure (according to DSSP classification) and to proteins without any introductory classified analysis, revealed that several of the discriminated groups of proteins agree with the assumed model of early-stage conformational sub-space. This analysis shows that protein structures may be represented in VR space instead of Phi, Psi angles space, thus lowering the conformational space dimensionality. The VR model allows classification of traditional secondary structure elements as well as different Random Coil motifs, which broadens the range of recognized structural categories (compared to standard secondary structure elements).
Collapse
Affiliation(s)
- W Jurkowski
- Department of Bioinformatics and Telemedicine, Jagiellonian University-Medical College, Department of Bioinformatics and Telemedicine, Lazarza 16, 31-530 Krakow, Poland
| | | | | |
Collapse
|
3
|
Hirani TA, Tovar-Méndez A, Miernyk JA, Randall DD. Asp295 stabilizes the active-site loop structure of pyruvate dehydrogenase, facilitating phosphorylation of ser292 by pyruvate dehydrogenase-kinase. Enzyme Res 2011; 2011:939068. [PMID: 21318135 PMCID: PMC3034952 DOI: 10.4061/2011/939068] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2010] [Accepted: 11/05/2010] [Indexed: 01/22/2023] Open
Abstract
We have developed an in vitro system for detailed analysis of reversible phosphorylation of the plant mitochondrial pyruvate dehydrogenase complex, comprising recombinant Arabidopsis thalianaα2β2-heterotetrameric pyruvate dehydrogenase (E1) plus A. thaliana E1-kinase (AtPDK). Upon addition of MgATP, Ser292, which is located within the active-site loop structure of E1α, is phosphorylated. In addition to Ser292, Asp295 and Gly297 are highly conserved in the E1α active-site loop sequences. Mutation of Asp295 to Ala, Asn, or Leu greatly reduced phosphorylation of Ser292, while mutation of Gly297 had relatively little effect. Quantitative two-hybrid analysis was used to show that mutation of Asp295 did not substantially affect binding of AtPDK to E1α. When using pyruvate as a variable substrate, the Asp295 mutant proteins had modest changes in kcat, Km, and kcat/Km values. Therefore, we propose that Asp295 plays an important role in stabilizing the active-site loop structure, facilitating transfer of the γ-phosphate from ATP to the Ser residue at regulatory site one of E1α.
Collapse
Affiliation(s)
- Tripty A Hirani
- Department of Biochemistry, University of Missouri, Columbia, MO 65211, USA
| | | | | | | |
Collapse
|
4
|
Georgiou T, Chuang JL, Wynn RM, Stylianidou G, Korson M, Chuang DT, Drousiotou A. Maple syrup urine disease in Cypriot families: identification of three novel mutations and biochemical characterization of the p.Thr211Met mutation in the E1alpha subunit. Genet Test Mol Biomarkers 2010; 13:657-64. [PMID: 19715473 DOI: 10.1089/gtmb.2009.0065] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
We report five mutations, three of them novel, responsible for maple syrup urine disease in four unrelated Cypriot families. The five children studied are the first cases of classic maple syrup urine disease to be reported among Cypriots. The first novel mutation identified is a single-base deletion in exon 6 of the Elalpha gene (c.718delG), which leads to a frameshift after Ala240 and to a stop codon 89 residues further downstream. The other two novel mutations identified are in the Elbeta subunit: a two-base deletion in exon 6, c.662_663delCC, which leads to a frameshift after Ala221 and creates a stop codon 17 residues further downstream, as well as a splice mutation, IVS3[+3]delA, which results in the skipping of exon 3. The two known mutations identified are in the Elalpha gene: the G > C transversion at the 3'-splice acceptor site, (IVS5-1G > C), which results in the deletion of the entire exon 6, and the missense mutation in exon 5 (c.632C > T), which corresponds to a p.Thr211Met substitution. The p.Thr211Met substitution is located in a potassium-ion pocket in the E1 component required for stability of the bound cofactor thiamine diphosphate. The mutant E1 protein harboring the p.Thr211Met substitution was shown unable to bind thiamine diphosphate, leading to undetectable E1 activity.
Collapse
Affiliation(s)
- Theodoros Georgiou
- Department of Biochemical Genetics, The Cyprus Institute of Neurology and Genetics, Nicosia, Cyprus
| | | | | | | | | | | | | |
Collapse
|
5
|
GroEL assisted folding of large polypeptide substrates in Escherichia coli: Present scenario and assignments for the future. PROGRESS IN BIOPHYSICS AND MOLECULAR BIOLOGY 2009; 99:42-50. [DOI: 10.1016/j.pbiomolbio.2008.10.007] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
|
6
|
Gräslund S, Nordlund P, Weigelt J, Hallberg BM, Bray J, Gileadi O, Knapp S, Oppermann U, Arrowsmith C, Hui R, Ming J, dhe-Paganon S, Park HW, Savchenko A, Yee A, Edwards A, Vincentelli R, Cambillau C, Kim R, Kim SH, Rao Z, Shi Y, Terwilliger TC, Kim CY, Hung LW, Waldo GS, Peleg Y, Albeck S, Unger T, Dym O, Prilusky J, Sussman JL, Stevens RC, Lesley SA, Wilson IA, Joachimiak A, Collart F, Dementieva I, Donnelly MI, Eschenfeldt WH, Kim Y, Stols L, Wu R, Zhou M, Burley SK, Emtage JS, Sauder JM, Thompson D, Bain K, Luz J, Gheyi T, Zhang F, Atwell S, Almo SC, Bonanno JB, Fiser A, Swaminathan S, Studier FW, Chance MR, Sali A, Acton TB, Xiao R, Zhao L, Ma LC, Hunt JF, Tong L, Cunningham K, Inouye M, Anderson S, Janjua H, Shastry R, Ho CK, Wang D, Wang H, Jiang M, Montelione GT, Stuart DI, Owens RJ, Daenke S, Schütz A, Heinemann U, Yokoyama S, Büssow K, Gunsalus KC. Protein production and purification. Nat Methods 2008; 5:135-46. [PMID: 18235434 PMCID: PMC3178102 DOI: 10.1038/nmeth.f.202] [Citation(s) in RCA: 614] [Impact Index Per Article: 38.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
In selecting a method to produce a recombinant protein, a researcher is faced with a bewildering array of choices as to where to start. To facilitate decision-making, we describe a consensus 'what to try first' strategy based on our collective analysis of the expression and purification of over 10,000 different proteins. This review presents methods that could be applied at the outset of any project, a prioritized list of alternate strategies and a list of pitfalls that trip many new investigators.
Collapse
|
7
|
KIM YOUNGCHANG, BIGELOW LANCE, BOROVILOS MARIA, DEMENTIEVA IRINA, DUGGAN ERIKA, HATZOS CATHERINE, JOACHIMIAK GRAZYNA, LI HUI, MULLIGAN RORY, QUARTEY PEARL, SATHER ALICIA, STOLS LUCY, VOLKART LOUR, ZHOU MIN, Volkart L, Wu R, Zhou M, Joachimiak A. Chapter 3. High-throughput protein purification for x-ray crystallography and NMR. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2008; 75:85-105. [PMID: 20731990 PMCID: PMC3366499 DOI: 10.1016/s0065-3233(07)75003-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
In structural biology, the most critical issue is the availability of high-quality samples. "Structural-biology-grade" proteins must be generated in a quantity and quality suitable for structure determination using X-ray crystallography or nuclear magnetic resonance. The additional challenge for structural genomics is the need for high numbers of proteins at low cost where protein targets quite often have low sequence similarities, unknown properties and are poorly characterized. The purification procedures must reproducibly yield homogeneous proteins or their derivatives containing marker atom(s) in milligram quantities. The choice of protein purification and handling procedures plays a critical role in obtaining high-quality protein samples. Where the ultimate goal of structural biology is the same-to understand the structural basis of proteins in cellular processes, the structural genomics approach is different in that the functional aspects of individual protein or family are not ignored, however, emphasis here is on the number of unique structures, covering most of the protein folding space and developing new technologies with high efficiency. At the Midwest Center Structural Genomics (MCSG), we have developed semiautomated protocols for high-throughput parallel protein purification. In brief, a protein, expressed as a fusion with a cleavable affinity tag, is purified in two immobilized metal affinity chromatography (IMAC) steps: (i) first IMAC coupled with buffer-exchange step, and after tag cleavage using TEV protease, (ii) second IMAC and buffer exchange to clean up cleaved tags and tagged TEV protease. Size exclusion chromatography is also applied as needed. These protocols have been implemented on multidimensional chromatography workstations AKTAexplorer and AKTAxpress (GE Healthcare). All methods and protocols used for purification, some developed in MCSG, others adopted and integrated into the MCSG purification pipeline and more recently the Center for Structural Genomics of Infectious Disease (CSGID) purification pipeline, are discussed in this chapter.
Collapse
|
8
|
Chen DH, Song JL, Chuang DT, Chiu W, Ludtke SJ. An expanded conformation of single-ring GroEL-GroES complex encapsulates an 86 kDa substrate. Structure 2007; 14:1711-22. [PMID: 17098196 DOI: 10.1016/j.str.2006.09.010] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2005] [Revised: 09/14/2006] [Accepted: 09/19/2006] [Indexed: 11/26/2022]
Abstract
Electron cryomicroscopy reveals an unprecedented conformation of the single-ring mutant of GroEL (SR398) bound to GroES in the presence of Mg-ATP. This conformation exhibits a considerable expansion of the folding cavity, with approximately 80% more volume than the X-ray structure of the equivalent cis cavity in the GroEL-GroES-(ADP)(7) complex. This expanded conformation can encapsulate an 86 kDa heterodimeric (alphabeta) assembly intermediate of mitochondrial branched-chain alpha-ketoacid dehydrogenase, the largest substrate ever observed to be cis encapsulated. The SR398-GroES-Mg-ATP complex is found to exist as a mixture of standard and expanded conformations, regardless of the absence or presence of the substrate. However, the presence of even a small substrate causes a pronounced bias toward the expanded conformation. Encapsulation of the large assembly intermediate is supported by a series of electron cryomicroscopy studies as well as the protection of both alpha and beta subunits of the substrate from tryptic digestion.
Collapse
Affiliation(s)
- Dong-Hua Chen
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, Texas 77030, USA
| | | | | | | | | |
Collapse
|
9
|
Song JL, Li J, Huang YS, Chuang DT. Encapsulation of an 86-kDa assembly intermediate inside the cavities of GroEL and its single-ring variant SR1 by GroES. J Biol Chem 2003; 278:2515-21. [PMID: 12431983 DOI: 10.1074/jbc.m209705200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We described previously that during the assembly of the alpha(2)beta(2) heterotetramer of human mitochondrial branched-chain alpha-ketoacid dehydrogenase (BCKD), chaperonins GroEL/GroES interact with the kinetically trapped heterodimeric (alphabeta) intermediate to facilitate conversion of the latter to the native BCKD heterotetramer. Here, we show that the 86-kDa heterodimeric intermediate possesses a native-like conformation as judged by its binding to a fluorescent probe 1-anilino-8-naphthalenesulfonate. This large heterodimeric intermediate is accommodated as an entity inside cavities of GroEL and its single-ring variant SR1 and is encapsulated by GroES as indicated by the resistance of the heterodimer to tryptic digestion. The SR1-alphabeta-GroES complex is isolated as a stable single species by gel filtration in the presence of Mg-ATP. In contrast, an unfolded BCKD fusion protein of similar size, which also resides in the GroEL or SR1 cavity, is too large to be capped by GroES. The cis-capping mechanism is consistent with the high level of BCKD activity recovered with the GroEL-alphabeta complex, GroES, and Mg-ATP. The 86-kDa native-like heterodimeric intermediate in the BCKD assembly pathway represents the largest protein substrate known to fit inside the GroEL cis cavity underneath GroES, which significantly exceeds the current size limit of 57 kDa established for unfolded proteins.
Collapse
Affiliation(s)
- Jiu-Li Song
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas 75390, USA
| | | | | | | |
Collapse
|
10
|
Abstract
During the past two years, a large amount of biochemical, biophysical and low- to high-resolution structural data have provided mechanistic insights into the machinery of protein folding and unfolding. It has emerged that dual functionality in terms of folding and unfolding might exist for some systems. The majority of folding/unfolding machines adopt oligomeric ring structures in a cooperative fashion and utilise the conformational changes induced by ATP binding/hydrolysis for their specific functions.
Collapse
Affiliation(s)
- Xiaodong Zhang
- Centre for Structural Biology, Department of Biological Sciences, Imperial College of Science, Technology and Medicine, Flowers Building, South Kensington, SW7 2AZ, London, UK.
| | | | | |
Collapse
|
11
|
Song JL, Chuang DT. Natural osmolyte trimethylamine N-oxide corrects assembly defects of mutant branched-chain alpha-ketoacid decarboxylase in maple syrup urine disease. J Biol Chem 2001; 276:40241-6. [PMID: 11507102 DOI: 10.1074/jbc.m107242200] [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: 11/06/2022] Open
Abstract
Maple syrup urine disease is caused by deficiency in the mitochondrial branched-chain alpha-ketoacid dehydrogenase (BCKD) complex. The clinical phenotype includes often fatal ketoacidosis, neurological derangement, and mental retardation. The type IA mutations Y393N-alpha, Y368C-alpha, and F364C-alpha, which occur in the E1alpha subunit of the decarboxylase (E1) component of the BCKD complex, impede the conversion of an alphabeta heterodimeric intermediate to a native alpha(2)beta(2) heterotetramer in the E1 assembly pathway. In the present study, we show that a natural osmolyte trimethylamine N-oxide (TMAO) at the optimal 1 m concentration restores E1 activity, up to 50% of the wild type, in the mutant E1 carrying the above missense mutations. TMAO promotes the conversion of otherwise trapped mutant heterodimers to active heterotetramers. This slow step does not involve dissociation/reassociation of the mutant heterodimers, which are preformed in the presence of chaperonins GroEL/GroES and Mg-ATP. The TMAO-stimulated mutant E1 activity is remarkably stable upon removal of the osmolyte, when cofactor thiamine pyrophosphate and the transacylase component of the BCKD complex are present. The above in vitro results offer the use of chemical chaperones such as TMAO as an approach to mitigate assembly defects caused by maple syrup urine disease mutations.
Collapse
Affiliation(s)
- J L Song
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75390-9038, USA
| | | |
Collapse
|
12
|
Wynn RM, Chuang JL, Sansaricq C, Mandel H, Chuang DT. Biochemical basis of type IB (E1beta ) mutations in maple syrup urine disease. A prevalent allele in patients from the Druze kindred in Israel. J Biol Chem 2001; 276:36550-6. [PMID: 11448970 DOI: 10.1074/jbc.m105862200] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Maple syrup urine disease (MSUD) is a metabolic disorder associated with often-fatal ketoacidosis, neurological derangement, and mental retardation. In this study, we identify and characterize two novel type IB MSUD mutations in Israeli patients, which affect the E1beta subunit in the decarboxylase (E1) component of the branched-chain alpha-ketoacid dehydrogenase complex. The recombinant mutant E1 carrying the prevalent S289L-beta (TCG --> TTG) mutation in the Druze kindred exists as a stable inactive alphabeta heterodimer. Based on the human E1 structure, the S289L-beta mutation disrupts the interactions between Ser-289-beta and Glu-290-beta', and between Arg-309-beta and Glu-290-beta', which are essential for native alpha(2)beta(2) heterotetrameric assembly. The R133P-beta (CGG --> CCG) mutation, on the other hand, is inefficiently expressed in Escherichia coli as heterotetramers in a temperature-dependent manner. The R133P-beta mutant E1 exhibits significant residual activity but is markedly less stable than the wild-type, as measured by thermal inactivation and free energy change of denaturation. The R133P-beta substitution abrogates the coordination of Arg-133-beta to Ala-95-beta, Glu-96-beta, and Ile-97-beta, which is important for strand-strand interactions and K(+) ion binding in the beta subunit. These findings provide new insights into folding and assembly of human E1 and will facilitate DNA-based diagnosis for MSUD in the Israeli population.
Collapse
Affiliation(s)
- R M Wynn
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, Texas 75390, USA
| | | | | | | | | |
Collapse
|
13
|
Ribbe MW, Burgess BK. The chaperone GroEL is required for the final assembly of the molybdenum-iron protein of nitrogenase. Proc Natl Acad Sci U S A 2001; 98:5521-5. [PMID: 11331775 PMCID: PMC33245 DOI: 10.1073/pnas.101119498] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
It is known that an E146D site-directed variant of the Azotobacter vinelandii iron protein (Fe protein) is specifically defective in its ability to participate in iron-molybdenum cofactor (FeMoco) insertion. Molybdenum-iron protein (MoFe protein) from the strain expressing the E146D Fe protein is partially ( approximately 45%) FeMoco deficient. The "free" FeMoco that is not inserted accumulates in the cell. We were able to insert this "free" FeMoco into the partially pure FeMoco-deficient MoFe protein. This insertion reaction required crude extract of the DeltanifHDK A. vinelandii strain CA12, Fe protein and MgATP. We used this as an assay to purify a required "insertion" protein. The purified protein was identified as GroEL, based on the molecular mass of its subunit (58.8 kDa), crossreaction with commercially available antibodies raised against E. coli GroEL, and its NH(2)-terminal polypeptide sequence. The NH(2)-terminal polypeptide sequence showed identity of up to 84% to GroEL from various organisms. Purified GroEL of A. vinelandii alone or in combination with MgATP and Fe protein did not support the FeMoco insertion into pure FeMoco-deficient MoFe protein, suggesting that there are still other proteins and/or factors missing. By using GroEL-containing extracts from a DeltanifHDK strain of A. vinelandii CA12 along with FeMoco, Fe protein, and MgATP, we were able to supply all required proteins and/or factors and obtained a fully active reconstituted E146D nifH MoFe protein. The involvement of the molecular chaperone GroEL in the insertion of a metal cluster into an apoprotein may have broad implications for the maturation of other metalloenzymes.
Collapse
Affiliation(s)
- M W Ribbe
- Department of Molecular Biology and Biochemistry, University of California, Irvine, CA 92697-3900, USA
| | | |
Collapse
|
14
|
Song JL, Wynn RM, Chuang DT. Interactions of GroEL/GroES with a heterodimeric intermediate during alpha 2beta 2 assembly of mitochondrial branched-chain alpha-ketoacid dehydrogenase. cis capping of the native-like 86-kDa intermediate by GroES. J Biol Chem 2000; 275:22305-12. [PMID: 10764784 DOI: 10.1074/jbc.m002038200] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
We showed previously that the interaction of an alphabeta heterodimeric intermediate with GroEL/GroES is essential for efficient alpha(2)beta(2) assembly of human mitochondrial branched-chain alpha-ketoacid dehydrogenase. In the present study, we further characterized the mode of interaction between the chaperonins and the native-like alphabeta heterodimer. The alphabeta heterodimer, as an intact entity, was found to bind to GroEL at a 1:1 stoichiometry with a K(D) of 1.1 x 10(-)(7) m. The 1:1 molar ratio of the GroEL-alphabeta complex was confirmed by the ability of the complex to bind a stoichiometric amount of denatured lysozyme in the trans cavity. Surprisingly, in the presence of Mg-ADP, GroES was able to cap the GroEL-alphabeta complex in cis, despite the size of 86 kDa of the heterodimer (with a His(6) tag and a linker). Incubation of the GroEL-alphabeta complex with Mg-ATP, but not AMP-PNP, resulted in the release of alpha monomers. In the presence of Mg-ATP, the beta subunit was also released but was unable to assemble with the alpha subunit, and rebound to GroEL. The apparent differential subunit release from GroEL is explained, in part, by the significantly higher binding affinity of the beta subunit (K(D) < 4.15 x 10(-9)m) than the alpha (K(D) = 1.6 x 10(-8)m) for GroEL. Incubation of the GroEL-alphabeta complex with Mg-ATP and GroES resulted in dissociation and discharge of both the alpha and beta subunits from GroEL. The beta subunit upon binding to GroEL underwent further folding in the cis cavity sequestered by GroES. This step rendered the beta subunit competent for reassociation with the soluble alpha subunit to produce a new heterodimer. We propose that this mechanism is responsible for the iterative annealing of the kinetically trapped heterodimeric intermediate, leading to an efficient alpha(2)beta(2) assembly of human branched-chain alpha-ketoacid dehydrogenase.
Collapse
Affiliation(s)
- J L Song
- Departments of Biochemistry and Internal Medicine, University of Texas Southwestern Medical Center, Dallas, Texas 75235, USA
| | | | | |
Collapse
|
15
|
Gottesman ME, Hendrickson WA. Protein folding and unfolding by Escherichia coli chaperones and chaperonins. Curr Opin Microbiol 2000; 3:197-202. [PMID: 10745003 DOI: 10.1016/s1369-5274(00)00075-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
Abstract
The folding of proteins from their initial unstructured state to their mature form has long been known to be promoted by other proteins known as chaperones and chaperonins. Recent biochemical and structural discoveries have provided dramatic insight into how these folding proteins work. This review will discuss these findings and suggest future experimental directions.
Collapse
Affiliation(s)
- M E Gottesman
- Departments of Microbiology and of Biochemistry and Molecular Biophysics, Institute of Cancer Research, Columbia University, New York, NY 10032, USA.
| | | |
Collapse
|