BIOB10H3 Lecture Notes - Lecture 12: X-Ray Crystallography, Sequence Database, Radiography
Document Summary
Step 1 : protein purification -we know how to do this = lecture 6: studying proteins. Now we can start to answer some these scientific questions . Primary protein sequence: mass spectrometry: what is the primary sequence of my protein of interest? that is, determining the order of its amino acids. Protein purified from cell extract - may be cut out of a 2-d gel. Protein is broken into smaller pieces (peptides) using a protease like trypsin. These peptides are dried on to a metal plate & heated by a laser. Makes peptides electrically charged (ionized) positive ions knock one or more electrons off. Fired from the plate as a gas through a magnetic field within a machine called a mass spectrometer. Peptide ions separate from each other based on their mass and charge; smaller ions travel faster than larger ions; highly charged ones move faster also separate according to their mass to charge ratio = m/z.
