Probing why trypanosomes assemble atypical cytochrome c with an AxxCH haem-binding motif instead of CxxCH

Michael L. Ginger, Katharine A. Sam, James W.A. Allen

Research output: Contribution to journalArticle

7 Citations (Scopus)

Abstract

Mitochondrial cytochromes c and c1 are core components of the respiratory chain of all oxygen-respiring eukaryotes. These proteins contain haem, covalently bound to the polypeptide in a catalysed post- translationalmodification. In all eukaryotes, except members of the protist phylum Euglenozoa, haem attachment is to the cysteine residues of a CxxCH haem-binding motif. In the Euglenozoa, which include medically relevant trypanosomatid parasites, haem attachment is to a single cysteine residue in an AxxCH haem-binding motif. Moreover, genes encoding known c-type cytochrome biogenesis machineries are all absent from trypanosomatid genomes, indicating the presence of a novel biosynthetic apparatus. In the present study, we investigate expression and maturation of cytochrome c with a typical CxxCH haem-binding motif in the trypanosomatids Crithidia fasciculata and Trypanosoma brucei. Haem became attached to both cysteine residues of the haem-binding motif, indicating that, in contrast with previous hypotheses, nothing prevents formation of a CxxCH cytochrome c in euglenozoan mitochondria. The cytochrome variant was also able to replace the function of wildtype cytochrome c in T. brucei. However, the haem attachment to protein was not via the stereospecifically conserved linkage universally observed in natural c-type cytochromes, suggesting that the trypanosome cytochrome c biogenesis machinery recognized and processed only the wild-type single-cysteine haem-binding motif. Moreover, the presence of the CxxCH cytochrome c resulted in a fitness cost in respiration. The level of cytochrome c biogenesis in trypanosomatids was also found to be limited, with the cells operating at close to maximum capacity.

LanguageEnglish
Pages253-260
Number of pages8
JournalBiochemical Journal
Volume448
Issue number2
DOIs
Publication statusPublished - 1 Dec 2012
Externally publishedYes

Fingerprint

Trypanosomiasis
Cytochromes c
Heme
Euglenozoa
Cysteine
Cytochrome c Group
Eukaryota
Crithidia fasciculata
Cytochromes c1
Trypanosoma brucei brucei
Mitochondria
Gene encoding
Cytochromes
Electron Transport
Machinery
Respiration
Parasites
Proteins
Genes
Genome

Cite this

@article{7c37615457e1442fa20c3545b504f1dc,
title = "Probing why trypanosomes assemble atypical cytochrome c with an AxxCH haem-binding motif instead of CxxCH",
abstract = "Mitochondrial cytochromes c and c1 are core components of the respiratory chain of all oxygen-respiring eukaryotes. These proteins contain haem, covalently bound to the polypeptide in a catalysed post- translationalmodification. In all eukaryotes, except members of the protist phylum Euglenozoa, haem attachment is to the cysteine residues of a CxxCH haem-binding motif. In the Euglenozoa, which include medically relevant trypanosomatid parasites, haem attachment is to a single cysteine residue in an AxxCH haem-binding motif. Moreover, genes encoding known c-type cytochrome biogenesis machineries are all absent from trypanosomatid genomes, indicating the presence of a novel biosynthetic apparatus. In the present study, we investigate expression and maturation of cytochrome c with a typical CxxCH haem-binding motif in the trypanosomatids Crithidia fasciculata and Trypanosoma brucei. Haem became attached to both cysteine residues of the haem-binding motif, indicating that, in contrast with previous hypotheses, nothing prevents formation of a CxxCH cytochrome c in euglenozoan mitochondria. The cytochrome variant was also able to replace the function of wildtype cytochrome c in T. brucei. However, the haem attachment to protein was not via the stereospecifically conserved linkage universally observed in natural c-type cytochromes, suggesting that the trypanosome cytochrome c biogenesis machinery recognized and processed only the wild-type single-cysteine haem-binding motif. Moreover, the presence of the CxxCH cytochrome c resulted in a fitness cost in respiration. The level of cytochrome c biogenesis in trypanosomatids was also found to be limited, with the cells operating at close to maximum capacity.",
keywords = "Cytochrome, Cytochrome c biogenesis, Euglenozoa, Haem, Trypanosome",
author = "Ginger, {Michael L.} and Sam, {Katharine A.} and Allen, {James W.A.}",
year = "2012",
month = "12",
day = "1",
doi = "10.1042/BJ20120757",
language = "English",
volume = "448",
pages = "253--260",
journal = "Biochemical Journal",
issn = "0264-6021",
publisher = "Portland Press Ltd.",
number = "2",

}

Probing why trypanosomes assemble atypical cytochrome c with an AxxCH haem-binding motif instead of CxxCH. / Ginger, Michael L.; Sam, Katharine A.; Allen, James W.A.

In: Biochemical Journal, Vol. 448, No. 2, 01.12.2012, p. 253-260.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Probing why trypanosomes assemble atypical cytochrome c with an AxxCH haem-binding motif instead of CxxCH

AU - Ginger, Michael L.

AU - Sam, Katharine A.

AU - Allen, James W.A.

PY - 2012/12/1

Y1 - 2012/12/1

N2 - Mitochondrial cytochromes c and c1 are core components of the respiratory chain of all oxygen-respiring eukaryotes. These proteins contain haem, covalently bound to the polypeptide in a catalysed post- translationalmodification. In all eukaryotes, except members of the protist phylum Euglenozoa, haem attachment is to the cysteine residues of a CxxCH haem-binding motif. In the Euglenozoa, which include medically relevant trypanosomatid parasites, haem attachment is to a single cysteine residue in an AxxCH haem-binding motif. Moreover, genes encoding known c-type cytochrome biogenesis machineries are all absent from trypanosomatid genomes, indicating the presence of a novel biosynthetic apparatus. In the present study, we investigate expression and maturation of cytochrome c with a typical CxxCH haem-binding motif in the trypanosomatids Crithidia fasciculata and Trypanosoma brucei. Haem became attached to both cysteine residues of the haem-binding motif, indicating that, in contrast with previous hypotheses, nothing prevents formation of a CxxCH cytochrome c in euglenozoan mitochondria. The cytochrome variant was also able to replace the function of wildtype cytochrome c in T. brucei. However, the haem attachment to protein was not via the stereospecifically conserved linkage universally observed in natural c-type cytochromes, suggesting that the trypanosome cytochrome c biogenesis machinery recognized and processed only the wild-type single-cysteine haem-binding motif. Moreover, the presence of the CxxCH cytochrome c resulted in a fitness cost in respiration. The level of cytochrome c biogenesis in trypanosomatids was also found to be limited, with the cells operating at close to maximum capacity.

AB - Mitochondrial cytochromes c and c1 are core components of the respiratory chain of all oxygen-respiring eukaryotes. These proteins contain haem, covalently bound to the polypeptide in a catalysed post- translationalmodification. In all eukaryotes, except members of the protist phylum Euglenozoa, haem attachment is to the cysteine residues of a CxxCH haem-binding motif. In the Euglenozoa, which include medically relevant trypanosomatid parasites, haem attachment is to a single cysteine residue in an AxxCH haem-binding motif. Moreover, genes encoding known c-type cytochrome biogenesis machineries are all absent from trypanosomatid genomes, indicating the presence of a novel biosynthetic apparatus. In the present study, we investigate expression and maturation of cytochrome c with a typical CxxCH haem-binding motif in the trypanosomatids Crithidia fasciculata and Trypanosoma brucei. Haem became attached to both cysteine residues of the haem-binding motif, indicating that, in contrast with previous hypotheses, nothing prevents formation of a CxxCH cytochrome c in euglenozoan mitochondria. The cytochrome variant was also able to replace the function of wildtype cytochrome c in T. brucei. However, the haem attachment to protein was not via the stereospecifically conserved linkage universally observed in natural c-type cytochromes, suggesting that the trypanosome cytochrome c biogenesis machinery recognized and processed only the wild-type single-cysteine haem-binding motif. Moreover, the presence of the CxxCH cytochrome c resulted in a fitness cost in respiration. The level of cytochrome c biogenesis in trypanosomatids was also found to be limited, with the cells operating at close to maximum capacity.

KW - Cytochrome

KW - Cytochrome c biogenesis

KW - Euglenozoa

KW - Haem

KW - Trypanosome

UR - http://www.scopus.com/inward/record.url?scp=84869069160&partnerID=8YFLogxK

U2 - 10.1042/BJ20120757

DO - 10.1042/BJ20120757

M3 - Article

VL - 448

SP - 253

EP - 260

JO - Biochemical Journal

T2 - Biochemical Journal

JF - Biochemical Journal

SN - 0264-6021

IS - 2

ER -