Purification and characterization of a lipid transfer particle in Rhodnius prolixus: phospholipid transfer.
In this study we report the purification and characterization of a lipid transfer particle (LTP) from Rhodnius prolixus hemolymph, and its participation in phospholipid and diacylglycerol transfer processes. (3)H-diacylglycerol labeled low density lipophorin from Manduca sexta ((3)H-LDLp) was incubated with R. prolixus lipophorin (Lp) in the presence of Rhodnius hemolymph. Following incubation and isolation, both lipoproteins showed equivalent amounts of (3)H-labeled lipids. Hemolymph was subjected to KBr gradient ultracentrifugation. SDS-PAGE analysis of gradient fractions showed the enrichment of bands with molecular masses similar to the M. sexta LTP standard. LTP containing fractions were assayed and lipid transfer activity was observed. Purification of LTP was accomplished by (i) KBr density gradient ultracentrifugation, (ii) size exclusion, (iii) Cu(++) affinity and (iv) ion exchange chromatographies. LTP molecular mass was estimated approximately 770 kDa, comprising three apoproteins, apoLTP-I (315 kDa), apoLTP-II (85 kDa) and apoLTP-III (58 kDa). Phospolipid content of (32)P-LTP was determined after two-dimensional TLC. (32)P-phospholipid-labeled and unlabeled lipophorins, purified from R. prolixus were incubated in the presence of LTP resulting in the time-dependent transfer of phospholipids. LTP-mediated phospholipid transfer was not a selective process.
Departamento de Bioquímica Médica, Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil 21941-590.
D M
DM
Golodne
M C
MC
Van Heusden
K C
KC
Gondim
H
H
Masuda
G C
GC
Atella
D000818:Animals; D001059:Apoproteins / Q000302:isolation & purification / Q000378:metabolism*; D001692:Biological Transport; D002352:Carrier Proteins / Q000302:isolation & purification / Q000378:metabolism*; D005260:Female; D008074:Lipoproteins / Q000378:metabolism; D018402:Manduca; D010743:Phospholipids / Q000378:metabolism*; D012239:Rhodnius / Q000378:metabolism*
D001059:Apoproteins; D002352:Carrier Proteins; D008074:Lipoproteins; D010743:Phospholipids; C032830:lipophorin