Avogadro-Scale Molecular Self-Assembly in Biological Systems
Avogadro-Scale Engineering: Form and Function
November 18, 19 2003
The Bartos Theater
Building E15, MIT
Shuguang Zhang
Center for Biomedical Engineering, Center for Bits & Atoms
Massachusetts Institute of Technology
Cambridge, MA 02139, USA
Interior of a cell: billions of biomolecules form
structures & allow cells to function with little errors.
A walking Avogadro being
Each adult human is made of ~100
trillion cells (1014 cells)!
Guyton, A.C. & Hall, J.E. (2000) Text Book
of Medical Physiology 10th ed. W.B.
Saunders.
http://www.nobel.se/medicine/laureates/1999/press.html
Water Molecules Per Person
If each person weighs ~70 kilograms, or 70,000 grams,
~ 70% of that is water, i.e. 70,000 grams x 70% = 49,000
grams of water. Each molecule of water has a molecular weight of
18 daltons (oxygen = 16) + (2 hydrogens). Therefore:
18 grams = 1 mole (6.023x1023 water molecules = the
Avogadro number)
And… 49,000 grams divided by 18 gram/mole = 2,722 moles, or
2,722 x 6.023x1023 water molecules per person!
A molecule
of water.
Numbers of Nucleotides in DNA per Person
Each cell in a person contains 2 copies of the genome
(3.164x109 bases)-- one from the mother and one from
the father: 2 x 3.1647x109 bases/cell, or ~6.33x109 bases/cell.
Each adult person is made of ~1014 cells, or
6.33x109 bases/cell x 1014 cells/person = 6.33x1023 bases/person!
Numbers of Protein in Cells per Person
http://www.nobel.se/medicine/laureates/1999/press.html
Each cell contains ~ 1 billion (109) proteins.
Each adult is made of 1014 cells, or
109 proteins/cell x 1014 cells/person
= 1023 proteins/person!
The hemoglobin molecule
has 4 polypeptide
chains -- 2  and 2 .
Number of Lipid per Cell per Person
Each cell plasma membrane is made of ~200 million
lipids. However, each cell also has a nuclear membrane,
mitochondrial membranes, Golgi apparati, endoplasmic reticulum, etc. Collectively, the number of
lipids is ~109 per cell. Each person is made of ~1014 cells,
or 109 lipids/cell x 1014 cells/person = ~1023 lipids/person!
Myelin
surrounds
spinal cord
nerve fibers.
The Ribosome
Steve Santoso Yang, Biology/CBA Ph.D. Student
Monomeric Surfactant Peptides:
A6D, V6D, V6D2, L6D, KL6, KV6
Sylvain Vauthey & Steve Santoso (CBE)
V6D Peptide Nanotubes
V6D
100 nm
Sylvain Vauthey
PNAS, 4/2002,
Steve Santoso,
NanoLetters,
7/2002
Geoffrey von
Maltzahn
Langmuir, 5/2003
Peptide Nanotubes are made up of trillions of peptides
Billions of molecules self-assemble into ordered structures
Vauthey, et al., PNAS, April 16, 2002
What do they have in common?
Made by Human
Machines
Made by Nature
Molecular machines
Transportation
Assembly lines
Digital database
Copy machines
Bulldozer/Destroyer
Chain couplers
Train control center
Train tracks
Mail sorting machine
Electric Fences
Gates/keys & passes
Internet/www
Hemoglobin
Ribosomes
Nucleosomes
Polymerases
Proteases/proteosome
Ligases
Centrosome
Actin filament network
Protein sorting
Membranes
Ion channels
Neuron synapse