Eukaryotic translation initiation factor 5A-1 is a
protein
Proteins are large biomolecules and macromolecules that comprise one or more long chains of amino acid residue (biochemistry), residues. Proteins perform a vast array of functions within organisms, including Enzyme catalysis, catalysing metab ...
that in humans is encoded by the ''EIF5A''
gene
In biology, the word gene has two meanings. The Mendelian gene is a basic unit of heredity. The molecular gene is a sequence of nucleotides in DNA that is transcribed to produce a functional RNA. There are two types of molecular genes: protei ...
.
It is the only known protein to contain the unusual amino acid
hypusine 'N''ε-(4-amino-2-hydroxybutyl)-lysine which is synthesized on eIF5A at a specific
lysine
Lysine (symbol Lys or K) is an α-amino acid that is a precursor to many proteins. Lysine contains an α-amino group (which is in the protonated form when the lysine is dissolved in water at physiological pH), an α-carboxylic acid group ( ...
residue from the
polyamine
A polyamine is an organic compound having two or more amino groups. Alkyl polyamines occur naturally, but some are synthetic. Alkylpolyamines are colorless, hygroscopic, and water soluble. Near neutral pH, they exist as the ammonium derivatives. ...
spermidine
Spermidine is a polyamine compound () found in ribosomes and living tissues and having various metabolic functions within organisms.
Function
Spermidine is an Aliphatic compound, aliphatic polyamine. Spermidine synthase (SPDS) catalyzes its form ...
by two catalytic steps.
is the bacterial
homolog
In biology, homology is similarity in anatomical structures or genes between organisms of different taxa due to shared ancestry, ''regardless'' of current functional differences. Evolutionary biology explains homologous structures as retained her ...
of eIF5A, which is
modified post-translationally in a similar but distinct way.
Both proteins are believed to catalyze
peptide bond
In organic chemistry, a peptide bond is an amide type of covalent chemical bond linking two consecutive alpha-amino acids from C1 (carbon number one) of one alpha-amino acid and N2 (nitrogen number two) of another, along a peptide or protein cha ...
formation and help resolve
ribosomal stalls, making them
elongation factors
Elongation may refer to:
* Elongation (astronomy)
* Elongation (geometry)
* Elongation (plasma physics)
* Part of transcription of DNA into RNA of all types, including mRNA, tRNA, rRNA, etc.
* Part of translation (biology) of mRNA into proteins
* ...
despite the "
initiation factor
In molecular biology, initiation factors are proteins that bind to the small subunit of the ribosome during the initiation of Translation (genetics), translation, a part of protein biosynthesis.
Initiation factors can interact with repressors to ...
" name originally assigned.
Faundes-Banka syndrome
Germline
In biology and genetics, the germline is the population of a multicellular organism's cells that develop into germ cells. In other words, they are the cells that form gametes ( eggs and sperm), which can come together to form a zygote. They dif ...