Biology Reference
In-Depth Information
12.6 PROTEIN MAPPING: A BRIEF LITERATURE SURVEY
In the past years, AFM-based protein mapping has been applied in different
laboratories to a wide variety of cells. Horton
reviewed mapping
efforts on receptor distribution over a live cell surface together with the
basic principles of AFM and its application to biological ligand receptor
interaction analysis.
55
In this review, an example of mapping of vasoactive
intestinal peptide, one of the neuropeptides found in bone, was presented.
Recent progress in molecular recognition studies has also been reviewed by
Hinterdorfer and Dufrêne.
47,56
Dupres
et al.
et al.
57
determined the adhesion forces between the heparin-
binding haemagglutinin adhesin (HBHA) produced by
Mycobacterium
tuberculosis
and heparin (see
Chapter 15
). They mapped the distribution
of HBHA molecules on the surface of living mycobacteria and found that
the adhesin is not randomly distributed over the mycobacterial surface,
but concentrated into nanodomains. Robert
et al.
58
asked the question of
the biological relevance of the speciic bond properties revealed by single-
molecule studies and gave positive answers to the questions. These are the
questions we always have to remember. (i) Which parameters do we need
to know to predict the behaviour of an encounter between receptors and
ligands, (ii) which information is actually yielded by single-molecule studies
and (iii) is it possible to relate this information to molecular structure?
Dazzi
reported the construction of an AFM probe which inds the
local transient deformation induced by an infrared pulsed laser tuned at a
sample absorbing wavelength. The method is suitable for the identiication
of biological materials situated near or on the AFM probe.
Qiu
et al.
59
et al.
60
mapped the presence of the human pluripotent stem cell marker,
TRA-1-81 antigen, on a human embryonic stem cell. Popov
mapped
ceramides distribution in artiicial lipid monolayers. Mapping of glycolipids is
important in relation with the characterization of segregated lipid structures
such as lipid rafts. Gunning
et al.
61
et al.
62
mapped the surface of living Caco-2 human
intestinal epithelial cells using a colloidal AFM probe modiied with wheat
germ agglutinin which was reactive to the glycosylated extracellular domain III
of the epidermal growth factor receptor. They reported the value of 125 pN as
the mean unbinding force from the cell surface and found non-homogeneous
distribution of the receptors on the cell surface. The unbinding force of 125
pN was approximately twice as high as the value obtained by Afrin
et al.
54
on
the red blood cell surface when they used the same lectin to pull glycophorin
A. Unbinding force of
Psathyrella velutina
lectin from glycophorin A was also
in the range of 70 pN according to Yan
et al.
30
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