Chemical Biology 03 BLOOD. Biomolecular Structure Protein Structure 9/25/09. www.optics.rochester.edu/.../image007.gif . Chemical Biology 03 BLOOD. Biomolecular Structure Protein Structure Lecture 8: 9/25/09. Hierarchy of Protein Structure. Primary structure is determined by sequence
Lecture 8: 9/25/09
Fig 1.1 Branden & Tooz
13 atoms between hydrogen bonds.
* In this highly idealized image of myoglobin, all of the helices are represented as colored ribbons, which trace their backbone.
* For simplicity, all side groups are completely ignored.
* How many helices do you see?
See myoglobin file with Rasmol
R groups on the outside of helix:
Here, silk worms munch on mulberry leaves.. YUM
Note the H bonding within sheet that is inter-strand, and spacing pattern.
Note the R groups project above and below the sheets, and that the sheets aren’t perfectly flat, but are puckered in such a way that the knob of one R group fits into the upward pucker of sheet above.
Intersheet van der Waals interactions govern polymer properties
Identity of R groups determine tensile strengths, flexibilities, and price of different silks.
Parallel Beta Sheet
The twisted sheet is not purely parallel or antiparallel , but has a mixed orientation.
Note from the N-term.: strand/loop/helix/loop strand/loop/helix/loop repeat
This beta stranded barrel and tight loops create a shielded lantern to hold the fluorescing group (cyclized triad of amino acids shown below). If group were exposed to solvent, the light would be extinguished.
Myoglobin again, see loops
LOOPS CONNECTING TWO ANTIPARALLEL BETA STRANDS: