Linked Life Data

9708990

Source:http://linkedlifedata.com/resource/pubmed/id/9708990

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
33
pubmed:dateCreated
1998-9-10
pubmed:abstractText
Acid beta-glucosidase is a lysosomal membrane protein that cleaves the O-beta-D-glucosidic linkage of glucosylceramide and aryl-beta-glucosides. Full activity reconstitution of the pure enzyme requires phospholipids and saposin C, an 80 aa activator protein. The deficiency of the enzyme or activator leads to Gaucher disease. A conformational change of acid beta-glucosidase is shown to accompany activity reconstitution by selected phospholipids or, particularly, phospholipid/saposin C complexes by intrinsic fluorescence spectral shifts, fluorescence quenching, and circular dichroism (CD). Negatively charged phospholipid (NCP) interfaces with unsaturated fatty acid acyl chains (UFAC) induced concordant blue-shifts in tryptophanyl fluorescence spectra and a loss of beta-strand structure by CD. The enzyme required an unsaturated fatty acid acyl chain in proximity (10-11 A) within liposomal membranes for activation, fluorescence blue-shifts, and changes in CD spectra. Activity enhancements were greatest when UFAC and the negatively charged headgroup were present on the same phospholipid. NCPs with UFAC protected the enzyme from fluorescence quenching by aqueous agents (I-, Cs+, acrylamide, TEMPO). Phosphatidylcholine with doxyl spin-labeled fatty acid acyl chains at carbons 7, 10, or 16 quenched enzyme fluorescence only when in NCP/PC liposomes. Saposin C (Trp-free) induced additional activity and fluorescence spectral changes in the enzyme only in the presence of NCP liposomes containing UFA. CD spectral changes indicated saposin C and acid beta-glucosidase interaction only in the presence of NCPs with UFA. These studies show that acid beta-glucosidase requires interfaces composed of NCPs, containing UFAC, for penetration into the outer leaflet of membranes. Furthermore, this interaction induces essential conformational changes for saposin C binding and further enhancement of acid beta-glucosidase catalytic activity.
pubmed:grant
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Aug
pubmed:issn
0006-2960
pubmed:author
pubmed:issnType
Print
pubmed:day
18
pubmed:volume
37
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
11544-54
pubmed:dateRevised
2007-11-14
pubmed:meshHeading
pubmed-meshheading:9708990-Animals, pubmed-meshheading:9708990-Chickens, pubmed-meshheading:9708990-Circular Dichroism, pubmed-meshheading:9708990-Enzyme Activation, pubmed-meshheading:9708990-Fatty Acids, Unsaturated, pubmed-meshheading:9708990-Fluorescence Polarization, pubmed-meshheading:9708990-Glucosylceramidase, pubmed-meshheading:9708990-Glycoproteins, pubmed-meshheading:9708990-Humans, pubmed-meshheading:9708990-Liposomes, pubmed-meshheading:9708990-Phosphatidic Acids, pubmed-meshheading:9708990-Phosphatidylcholines, pubmed-meshheading:9708990-Phosphatidylglycerols, pubmed-meshheading:9708990-Phosphatidylserines, pubmed-meshheading:9708990-Phospholipids, pubmed-meshheading:9708990-Protein Conformation, pubmed-meshheading:9708990-Saposins, pubmed-meshheading:9708990-Spectrometry, Fluorescence
pubmed:year
1998
pubmed:articleTitle
Acid beta-glucosidase: intrinsic fluorescence and conformational changes induced by phospholipids and saposin C.
pubmed:affiliation
The Division of Human Genetics, Children's Hospital Research Foundation, Cincinnati, Ohio 45229-3039, USA.
pubmed:publicationType
Journal Article, Research Support, U.S. Gov't, P.H.S., Research Support, Non-U.S. Gov't