Linked Life Data

12498803

Source:http://linkedlifedata.com/resource/pubmed/id/12498803

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
3
pubmed:dateCreated
2002-12-24
pubmed:abstractText
Atomic force microscopy (AFM) has developed into a powerful tool to investigate membrane protein surfaces in a close-to-native environment. Here we report on the surface topography of Rhodobacter sphaeroides light harvesting complex 2 (LH2) reconstituted into two-dimensional crystals. These photosynthetic trans-membrane proteins formed cylindrical oligomeric complexes, which inserted tilted into the lipid membrane. This peculiar packing of an integral membrane protein allowed us to determine oligomerization and tilt of the LH2 complexes, but also protrusion height and intrinsic flexibility of their individual subunits. Furthermore the surface contouring reliability and limits of the atomic force microscopy could be studied. The two-dimensional crystals examined had sizes of up to 5 microm and, as revealed by a 10 A cryo electron microscopy projection map, p22(1)2(1) crystal symmetry. The unit cell had dimensions of a = b = 150 A and gamma = 90 degrees, and housed four nonameric complexes, two pointing up and two pointing down. AFM topographs of these 2D crystals had a lateral resolution of 10 A. Further, the high vertical resolution of approximately 1 A, allowed the protrusion height of the cylindrical LH2 complexes over the membrane to be determined. This was maximally 13.1 A on one side and 3.8 A on the other. Interestingly, the protrusion height varied across the LH2 complexes, showing the complexes to be inserted with a 6.2 degree tilt with respect to the membrane plane. A detailed analysis of the individual subunits showed the intrinsic flexibility of the membrane protruding peptide stretches to be equal and independent of their protrusion height. Furthermore, our analysis of membrane proteins within this peculiar packing confirmed the high vertical resolution of the atomic force microscopy on biological samples, and led us to conclude that the image acquisition function was equally accurate for contouring protrusions with heights up to approximately 15 A.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jan
pubmed:issn
0022-2836
pubmed:author
pubmed:copyrightInfo
Copyright 2003 Elsevier Science Ltd.
pubmed:issnType
Print
pubmed:day
17
pubmed:volume
325
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
569-80
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
2003
pubmed:articleTitle
AFM characterization of tilt and intrinsic flexibility of Rhodobacter sphaeroides light harvesting complex 2 (LH2).
pubmed:affiliation
Institut Curie, UMR-CNRS 168 and LRC-CEA 34V, 11 rue Pierre et Marie Curie, 75231 Paris Cedex 05, France. simon.scheuring@curie.fr
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't