7kzm is a 24 chain structure with sequence from Chlamydomonas reinhardtii. Full crystallographic information is available from OCA. For a guided tour on the structure components use FirstGlance.
TBB_CHLRE Tubulin is the major constituent of microtubules. It binds two moles of GTP, one at an exchangeable site on the beta chain and one at a non-exchangeable site on the alpha chain.