Last modified 21st Jul '95 © Birkbeck College 1995

Protein Interactions

Updated 21st Jul, 13th Jul, 30th Jun, 26th Jun, 9th Jun, 6th Jun, 25th May ; see below Back to Main Index

To best appreciate the content of this chapter you need to INTERACTIVELY EXAMINE a number of protein structures. If you haven't done so already, we STRONGLY URGE you to install the FREE molecular viewer software, RasMol and configure it to be automatically invoked by chemical/MIME. See our Technology Page to find out how.

This chapter aims to describe a few of the ways that proteins interact with each other and with other large molecules in cells.

Protein-Protein Interactions

Proteins are directed to the correct compartments of cells by binding to other proteins. Protein messengers bind to protein receptors on the outer surface of cell membranes to send signals between cells. Proteins form structural connections between cells. Some inhibitors of enzymes are proteins. Proteins are modified and degraded by enzymes. Interactions between different protein subunits are the basis of allosteric changes in multimers. Protein-protein interactions underlie very large-scale movements in organisms, such as muscle contraction.

Protein-Nucleic Acid Interactions

Certain proteins (histones) are an integral part of chromatin, which is the wound form of DNA which constitutes chromosomes. Enzymes perform the transcription of DNA to form RNA, while other proteins bind to specific regions of DNA to promote or inhibit its transcription; thus gene regulation. In fact we mean just about all the cellular machinery for synthesis, replication, manipulation, modification, and degradation.

Protein Interactions with other biological (macro)molecules

This chapter also includes material on the enzymes which degrade polysaccharides and lipids.

Some of the following sections are still unfinished; some sections have been completed in the last week or so. Meanwhile, theres still plenty there to be getting on with...
Thu 25th May: Inhibition page now ready
Mon 5th Jun: Muscle Fibres page now ready
Fri 9th Jun: Regulation page now includes link to Homeodomains section
Mon 26th Jun: Regulation page now includes link to lac repressor section
Fri 30th Jun: Proteases (Lysis- polypeptides) page now includes link to Serine Proteases section
Thu 13th Jul: Muscle Fibres page 3 now includes link to animation
Fri 21st Jul: Protein hydration: experimental and simulated

Binding

Targeting and Transport of Proteins
Inhibition
Regulation of DNA and proteins
Messaging- hormones and receptors
Adhesion

Lysis

of Polypeptides; 4 families of proteases
of Polysaccharides
of Lipids

Conformational changes

Allostery
Larger scale movements e.g. muscle fibres
Database of Protein Motions maintained by Mark Gerstein at Stanford.

Protein Degradation

The turnover of protein is more than simply their proteolysis. Refer back to the section covering this aspect in the Protein Synthesis chapter.

Protein-Solvent Interactions

Experimental data on protein hydration structure
Computer simulation of hydration structure

If you have MAGE installed and configured for Chemical MIME, you can view the Branden and Tooze, Protein Science and Protein Tourist Kinemages, some of which are relevant to this materi al. Again, refer to the Technology Page if necessary. There are some links to appropriate Kinemages within this chapter.

Credits
We wish to thank the following for material incorporated into this chapter

Daniel Barsky
Henry Brzeski
Sophie Clarke
Mark Dalton
Mark Gerstein
Donovan Haines
Judith Murray-Rust
Manuel Peitsch & Swiss-3DProt
M.I.T.

Back to Main PPS Index
J. Walshaw & Alan Mills