Chemistry Seminar Series: Professor Graeme HunterExport this event to calendar

Wednesday, November 23, 2011 — 2:30 PM to 3:30 PM EST

Protein-crystal interactions in biomineralization

Professor Graeme K. Hunter
Schulich School of Medicine & Dentistry
University of Western Ontario

Abstract:  Biomineralization is usually understood to mean deposition of crystals in hard tissues such as bones, teeth and shells.  However, crystals can also form in soft tissues and body fluids, resulting in ectopic calcifications such as atherosclerotic plaque, kidney stones and dental calculus.  Over the last decade, several proteins that prevent soft-tissue calcification have been identified, but their mechanisms of action are not well understood.  My collaborators and I study osteopontin (OPN), which acts to prevent crystal deposition in a variety of soft tissues, and matrix gla protein (MGP), which inhibits calcification of blood vessels.  The effects of these proteins on the biominerals hydroxyapatite (which occurs in atherosclerotic plaque) and calcium oxalate monohydrate (the principal mineral phase of kidney stones) are being investigated using peptide synthesis, autotitration, confocal microscopy, atomic force microscopy and molecular dynamics.  We have shown that OPN and MGP preferentially adsorb to basic crystal planes such as the {100} face of calcium oxalate monohydrate.  Post-translational modifications (phosphorylation and ã-carboxylation) play important roles in these interactions.  Based on these findings, we have proposed that protein-crystal interactions do not involve a stereochemical complementarity between protein and crystal, as is generally believed, but rather is governed by electrostatics and flexibility of the peptide backbone.  Our recent studies suggest mechanisms by which adsorption of acidic proteins and peptides to specific lattice planes can result in inhibition of crystal growth, modification of growth habit (size and shape) or incorporation of protein/peptide into the crystal lattice.

Location 
C2 - Chemistry 2
Room 361
200 University Ave West

Waterloo, ON N2L 3G1
Canada

S M T W T F S
27
28
29
30
31
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
  1. 2019 (126)
    1. November (10)
    2. October (13)
    3. September (18)
    4. August (4)
    5. July (9)
    6. June (9)
    7. May (15)
    8. April (13)
    9. March (15)
    10. February (14)
    11. January (6)
  2. 2018 (115)
    1. December (5)
    2. November (14)
    3. October (11)
    4. September (5)
    5. August (5)
    6. July (4)
    7. June (5)
    8. May (8)
    9. April (13)
    10. March (12)
    11. February (15)
    12. January (18)
  3. 2017 (108)
  4. 2016 (125)
  5. 2015 (115)
  6. 2014 (98)
  7. 2013 (104)
  8. 2012 (85)
  9. 2011 (10)