In ValRS, the side chain of Asp 279 protrudes into the editing active site, where it hydrogen-bonds with the hydroxyl group of threonine. The isosteric (having the same shape) valine lacks this hydroxyl group and is thereby excluded from the editing pocket.

TLS Online TPP Program

#Id: 10467

#Unit 4. Cell Communication and Cell Signaling

Sporadic retinoblastoma, inherit two normal RB alleles, each of which has undergone a LOF somatic mutation in a single retinal cell

TLS Online TPP Program

#Id: 2874

#Unit 13. Methods in Biology

The Beer–Lambert law is valid for low concentrations only.

TLS Online TPP Program

#Id: 10097

#Unit 4. Cell Communication and Cell Signaling

Three major classes of animal-cell junctions: 

1. Anchoring junctions

2. Tight junctions

3. Gap junctions

TLS Online TPP Program

#Id: 10469

#Unit 4. Cell Communication and Cell Signaling

Three mechanisms for LOH of tumor-suppressor genes:

Inactivating mutation or deletion

Chromosome missegregation

Mitotic recombination

TLS Online TPP Program

#Id: 7221

#Unit 5. Developmental Biology

Time course of appearance of  thymocytes and  thymocytes during mouse fetal development.