Glu35

Glu35 is a shorthand designation used in protein science to identify a specific amino acid residue within a polypeptide chain. It denotes glutamic acid (three-letter code Glu, one-letter code E) occupying residue number 35 in the protein’s sequence or chain. The label is context-dependent: many distinct proteins can have a Glu35 in different chains or isoforms, and numbering may vary with processing or alternative splicing.

Chemical and structural properties

Glutamic acid is a polar, negatively charged amino acid at physiological pH due to its side-chain carboxyl group. In proteins, the side chain is typically deprotonated (carboxylate form) with a pKa around 4.1, though the local environment can shift this value. As a consequence, Glu35 can participate in electrostatic interactions, hydrogen bonding, and salt-bridge formations with positively charged residues such as lysine or arginine. It can also contribute to the chemical properties of active sites, substrate binding pockets, or allosteric networks, and, in some cases, coordinate metal ions.

Functional relevance and study

The functional importance of Glu35 is determined by its structural context. Researchers study Glu35 through methods including site-directed mutagenesis (for example, substituting Glu with Gln or Ala to assess the role of the negative charge or side-chain length), X-ray crystallography or cryo-electron microscopy to reveal its geometry, and NMR spectroscopy to observe its dynamics. Conservation of Glu at position 35 across homologous proteins can indicate functional significance, while variation may reflect divergent mechanisms.

Context and caveats

Residue numbering like Glu35 relies on the specific protein sequence and chain identifiers; processing events or alternative isoforms can shift numbering. Therefore, the designation is meaningful when paired with the protein, chain, and organism in question.