A novel phospholipase from Trypanosoma brucei

TY - JOUR

T1 - A novel phospholipase from Trypanosoma brucei

AU - Richmond, Gregory S.

AU - Smith, Terry K.

PY - 2007/2

Y1 - 2007/2

N2 - Phospholipase A(1) activities have been detected in most cells where they have been sought and yet their characterization lags far behind that of the phospholipases A(2), C and D. The study presented here details the first cloning and characterization of a cytosolic PLA(1) that exhibits preference for phosphatidylcholine (GPCho) substrates. Trypanosoma brucei phospholipase A(1) (TbPLA(1)) is unique from previously identified eukaryotic PLA(1) because it is evolutionarily related to bacterial secreted PLA(1). A T. brucei ancestor most likely acquired the PLA(1) from a horizontal gene transfer of a PLA(1) from Sodalis glossinidius, a bacterial endosymbiont of tsetse flies. Nano-electrospray ionization tandem mass spectrometry analysis of TbPLA(1) mutants established that the enzyme functions in vivo to synthesize lysoGPCho metabolites containing long-chain mostly polyunsaturated and highly unsaturated fatty acids. Analysis of purified mutated recombinant forms of TbPLA(1) revealed that this enzyme is a serine hydrolase whose catalytic mechanism involves a triad consisting of the amino acid residues Ser-131, His-234 and Asp-183. The TbPLA(1) homozygous null mutants generated here constitute the only PLA(1) double knockouts from any organism.

AB - Phospholipase A(1) activities have been detected in most cells where they have been sought and yet their characterization lags far behind that of the phospholipases A(2), C and D. The study presented here details the first cloning and characterization of a cytosolic PLA(1) that exhibits preference for phosphatidylcholine (GPCho) substrates. Trypanosoma brucei phospholipase A(1) (TbPLA(1)) is unique from previously identified eukaryotic PLA(1) because it is evolutionarily related to bacterial secreted PLA(1). A T. brucei ancestor most likely acquired the PLA(1) from a horizontal gene transfer of a PLA(1) from Sodalis glossinidius, a bacterial endosymbiont of tsetse flies. Nano-electrospray ionization tandem mass spectrometry analysis of TbPLA(1) mutants established that the enzyme functions in vivo to synthesize lysoGPCho metabolites containing long-chain mostly polyunsaturated and highly unsaturated fatty acids. Analysis of purified mutated recombinant forms of TbPLA(1) revealed that this enzyme is a serine hydrolase whose catalytic mechanism involves a triad consisting of the amino acid residues Ser-131, His-234 and Asp-183. The TbPLA(1) homozygous null mutants generated here constitute the only PLA(1) double knockouts from any organism.

KW - Amino Acid Sequence

KW - Animals

KW - Base Sequence

KW - Catalytic Domain

KW - Cloning, Molecular

KW - Cytosol

KW - Evolution, Molecular

KW - Hydrolysis

KW - Lysophosphatidylcholines

KW - Molecular Sequence Data

KW - Mutation

KW - Phosphatidylcholines

KW - Phospholipases A

KW - Phylogeny

KW - Recombinant Proteins

KW - Sequence Homology, Amino Acid

KW - Substrate Specificity

KW - Trypanosoma brucei brucei

U2 - 10.1111/j.1365-2958.2006.05582.x

DO - 10.1111/j.1365-2958.2006.05582.x

M3 - Article

C2 - 17238918

SN - 0950-382X

VL - 63

SP - 1078

EP - 1095

JO - Molecular Microbiology

JF - Molecular Microbiology

IS - 4

ER -