Closed applicato closed 6 years ago
Course materials are still available here:
https://ocw.mit.edu/courses/biology/7-28-molecular-biology-spring-2005/index.htm
It's not as interactive as EdX though.
Generally, when an MIT course on EdX is down, the course materials should still be accessible through Open Courseware.
Replaced the moleculer biology course with the link you showed, I believe MIT is trying to get their biology courses in their own website.
https://www.edx.org/course/molecular-biology-part-1-dna-replication-mitx-7-28-1x-1