The 5 INSERTED sequences in the spike protein

The 5 insert sequences in the Spike Protein are -
1. GTNGTKR at positions 77-83
2. YYHKNNKS at positions 149-156
3. GDSSSG at positions 257-262
4. ACE2 binding site at positions 440-511
5. QTNSPRRA at positions 682-689

So are these novel sequences bio-active?
It is a cardinal principle of pharmacodynamics that a drug is only bioactive if it binds to a receptor.
So the question becomes - do these protein sequences bind to receptors on human cells?
We already know that two of these inserts are bio-active - namely (4) and (5) above.
(4) binds to the ACE2 receptor blocking its normal function of converting angiotensin II into a less harmful substance. The result is a build up of angiotensin II. Angiotensin II triggers vaso-constriction, and the release of Thrombin - the result being clotting, Thrombocytopenia.
(5) binds to the acetylcholine receptors, disrupting their normal function of transmitting nerve impulses to muscles. The result is tremors, spasms, seizures, alzheimers, heart dysregulation.

A Working Hypothesis
IF the Spike is engineered as a bio-weapon, then it is reasonable to assume that ALL the novel sequences that differentiate it from other corona viruses are bioactive - put there to do harm.
It follows that ALL of the 5 sequences must each bind to a receptor. In doing so, these 5 sequences would impede the normal function of their receptors and induce pathology.
We have already seen how two of these sequences, (4) and (5), act as bio-weapons - binding to receptors and inducing crippling effects such as clotting and tremors.
If this hypothesis is correct, then we should find that the remaining 3 novel sequences were also chosen for their pathological effects - by disrupting the function of particular receptors.


First Attempt at Identifying Receptors for Sequence (1)
GTNGTKR
[link to www.ncbi.nlm.nih.gov (secure)]
"We searched the Protein Data Bank using the largest insert 72GTNGTKR78 with 5 amino acids extensions on both N- and C-terminal sides, leading to 17aa long segment 67AIHVSGTNGTKRFDNPV83; then we analyzed the hits to see whether the aligned motifs were engaged in any identified structural function"
"The first hit was the structure of the Mengo virus VP1 protein"
In case you haven't heard of Mengo Virus - it goes by a common name - Myocarditis.
Mengo virus is also known as Encephalomyocarditisvirus (EMCV). Myocarditis is characterized by cardiac inflammation. Other symptoms have been observed, such as anorexia, apathy, palsy, paralysis or dyspnea.
Myocarditis is what children have been developing after the V.

Outline of the Binding Sites on the Spike Protein
[link to febs.onlinelibrary.wiley.com (secure)]
This paper lists the following binding types and the location of the aminoacids involved -
ACE2
SIALIC ACID
SUGAR
HSPG
CLR
NRP1
PROTEASE CLEAVAGE