Peter, forgive my absence from AB for a few weeks. I've been otherwise occupied in this BSL level 4 laboratory and have had little time to myself in recent weeks.
B.1.617 is a double mutant virus with E484Q and L452R spike protein mutations currently being causes of concern. E484Q is remarkably similar to E484K mutation (aka "eek"mutation) that is present in the South African and Brazilian variants. L452R has previously been found in the B.1.427 and B.1.429 variants circulating wildly in California.
In the E484Q spike protein mutation, glutamine is substituted for glutamic acid. In theory, this diminishes ACE2 binding and may increase immune evasion. In the L452R, there is a leucine to arginine substitution with similar issues.
That's the technical stuff over. Laboratory work on B.1.617 is ongoing 24 hours a day and I hope to have the answers we need soon.