Start this free course now. Just create an account and sign in. Enrol and complete the course for a free statement of participation or digital badge if available.

Free course


5.4 Protein–protein interactions

You should by now be beginning to appreciate the importance of protein–protein interactions in different cellular processes. Indeed, such interactions are intrinsic to virtually every cellular process, e.g. DNA replication, transcription, translation, control of the cell cycle, signal transduction, secretory and metabolic processes.

There are three main types of protein–protein interaction, termed surface–string, helix–helix and surface–surface interactions (Figure 37).

Figure 37 The three main types of protein–protein contact.

Surface–surface interactions are the most common type of protein–protein contact. They require precise matching of complementary surfaces in the two proteins and tend to be relatively strong. The requirement for a good fit makes surface–surface interactions very specific.

In surface–string interactions, an extended loop of one protein makes contact with the surface of another protein. An example of this kind of interaction is that which occurs between a peptide containing a phosphotyrosine residue and the SH2 domain of Src and other related proteins. Another surface–string interaction takes place between the kinase fold of Src and part of the protein that it phosphorylates.

Helix–helix interactions involve α helices from two different proteins wrapping around each other to form a coiled-coil. Such an interaction occurs in a number of gene-regulatory proteins. Towards the end of this free course we will look at some of the techniques employed to study protein–protein interactions.


Take your learning further

Making the decision to study can be a big step, which is why you'll want a trusted University. The Open University has 50 years’ experience delivering flexible learning and 170,000 students are studying with us right now. Take a look at all Open University courses.

If you are new to University-level study, we offer two introductory routes to our qualifications. You could either choose to start with an Access module, or a module which allows you to count your previous learning towards an Open University qualification. Read our guide on Where to take your learning next for more information.

Not ready for formal University study? Then browse over 1000 free courses on OpenLearn and sign up to our newsletter to hear about new free courses as they are released.

Every year, thousands of students decide to study with The Open University. With over 120 qualifications, we’ve got the right course for you.

Request an Open University prospectus371