Greetings. Welcome to this lecture series, Principles of Biochemistry.
I'm Jerry Feigenson, a professor in
the Department of Molecular Biology and Genetics at Cornell University in the US.
In the third lecture, you saw that researchers can learn a lot from knowing
the amino acid sequence without yet
knowing the full three-dimensional structure of a protein.
The basic principles of protein crystallography
to find the three-dimensional structure were described,
six categories of interactions that determine protein structure were shown,
and you saw the consequences of the real size of atoms and peptide bond constraints,
which together greatly restrict the possible structures of proteins.
In this fourth lecture,
you will learn about protein secondary structures, alpha-helices, beta-sheets, turns,
and collagen, and you will learn that what we call the protein fold is stable,
and only about 1,400 different protein folds exist.
Proteins can be arranged according to the type of fold,
the superfamily and the family.
Before we get to protein folds,
let me show you where we are in the study of biochemistry.
We are here, protein structure.
We will soon be looking at enzyme catalysis,
then regulation of enzymes,
then carbohydrates and lipids and membranes, and metabolism.
In fact, for metabolism,
we will spend quite a number of lectures.
The interconnections and control of metabolism are based on proteins.
So we're here now with protein structure, and then soon,
we will notice what structures we observe,
we'll study how catalysts work,
and how enzymes are controlled.