Crystal structure of
Ice and Protein
PHYS 571
Yeliz Celik
Young Eun Choi
Andrew DiLullo
Outline
Ice Physical Properties Types of Ice Hexagonal Ice Structure (Ice Ih) Hydrogen bonding and the hexagonal structure of ice The hexamer and the hexagonal crystal structure
Protein Crystallization Examples of Protein structures
Ice Physical Properties
CHEMISTRY H2O , Hydrogen dioxide
CRYSTALLOGRAPHYH Hexagonal (Ih)
CRYSTAL GROWTH AND
HABITS
Generally flat hexagonal crystals
Ice also forms rounded and concentrically zoned spheres as hail stones. It can be stalactitic, and massive granular.
COLOR AND OTHER OPTICAL PROPERTIES
Clear to white, Pale blue, Greenish blue, transparent to translucent
HARDNESS 1.5
DENSITY 0.9167 g/cm3
BREAKABILITY Very brittle fracture producing small, conchoidal fragments
http://www.lsbu.ac.uk/water/phase.html
http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm
Water Phase Diagram and Morphology Diagram
Types of Ice- With both cooling and pressure different types exist : Ice II,III, V, VI, VII,VIII,
IX, and X. The types are differentiated by their crystalline structure, ordering and density.
- There are also two metastable phases of ice under pressure, both fully hydrogen disordered: IV and XII. - Ices XI, XIII, and XIV are hydrogen-ordered forms of ices Ih, V, and XII
respectively.
Ice II (rhombohedral) Ice III (tetragonal) Ice V (monoclinic)
Ice VI (tetragonal) Ice VIII (tetragonal) Ice X (cubic)
Types of Ice- Everyday ice and snow has a hexagonal crystal structure (ice Ih).
- Only a little less stable (metastable) than Ih is the cubic structure (Ic).
Prism face
http://www.lsbu.ac.uk/water/ice1h.html
a1
a2
c(a3)
a1= a2
a = 4.51Å, c =7.35Å
γ =120°
Hexagonal Ice Structure (Ice Ih)
•Hexagonal ice plate formed from vapor deposition in air at 0 to -3 or -10 to -35 ºC. LT-SEM image with inset light microscope image.
•Classic snowflake formed from vapor-rich air between -10 to -22 ºC . LT-SEM image with inset light
© Eric Erbe / Beltsville Agricultural Research Center
Hydrogen Bonding in Ice Hydrogen bonding in general:
shared bonding of H between two highly electronegative atoms such as F, O, or N
Hydrogen bonding in water and ice: isolated two molecule (dimer) system
Other isolated clusters of ice molecules trimer, tetramer,
pentamer, hexamer hexamer is the most
energetically likely
Isolated groups only somewhat useful in bulk study
Hydrogen bonding and the hexagonal structure of ice
The hexamer and the hexagonal crystal structure of ice
2.8Å O-O distance Reason for decreased
density of ice Expect 4 hydrogen
bonds per molecule Measured 3.69
hydrogen bonds per molecule
Protein Crystallization
Applications:
1. Drug design and structural biology
2. Bio-separation
3. Controlled drug delivery
Protein Crystallography
X-ray crystallography :
1. Protein structures at the atomic level
2. How proteins interact with other molecules
3. How they undergo conformational changes
Spruce Budworm Antifreeze Protein
Insect antifreeze protein Molecular weight is ~9 kDa Protects from freezing at T below 0
degrees
Protein Crystallography
Pure protein (an insect antifreeze protein) Sample needs to be concentrated Dilute buffer Hanging drop vapor diffusion method
Hanging Drop Vapor Diffusion Method
http://www.bio.davidson.edu/COURSES/Molbio/MolStudents/spring2003/Kogoy/protein.html
Crystals of Spruce budworm antifreeze proteins
After repeated seeding a nice crystal obtained
0.21X 0.12X 0.02 mm
Leinala et al.,2002: Grather,SP et al.,1999
Leinala et al.,2002
Crystals of recombinant Spruce budworm antifreeze proteins
Result of x-ray crystallography is a three dimensional map that shows the distribution of electrons in the structure.
http://www.jic.ac.uk/staff/david-lawson/xtallog/summary.htm
Crystal structure of the protein: Single Anomalous Scattering, NMR
Left-handed Beta helical structure 15 amino-acid loops
Leinala, EK et al., 2002
How shape morphology changes when ice crystal is grown in a solution of the insect antifreeze protein
References
Petrenko,VF, et al.,Physics of Ice,1999, Oxford University Press, New York
Grather,SP et al.,1999, Journal of Structural Biology,126,72-75. Leinala, EK, 2002, Structure,10,619-627. http://www.bio.davidson.edu/COURSES/Molbio/MolStudents/
spring2003/Kogoy/protein.html http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm http://www.lsbu.ac.uk/water/phase.html http://www.jic.ac.uk/staff/david-lawson/xtallog/summary.htm http://www.lsbu.ac.uk/water/phase.html http://www.its.caltech.edu/~atomic/snowcrystals/primer/primer.htm