Enaptin

spectrin repeat containing, nuclear envelope 1
Identifiers
Symbol	SYNE1
Entrez	23345
HUGO	17089
OMIM	608441
RefSeq	NM_182961
UniProt	Q8NF91
Other data
Locus	Chr. 6 q24.2-25.3

Enaptin (UniProt name: SYNE1_HUMAN; accession number: Q8NF91) is a nuclear envelope protein found in human myocytes and synapses, which is made up of 8,797 amino acids. Post-translational amino acid modifications can be possible. Enaptin is involved in the maintenance of nuclear organization and structural integrity, tethering the cell nucleus to the cytoskeleton by interacting with the nuclear envelope and with F-actin in the cytoplasm. Enaptin has a remarkable structure with a coiled alpha-helical region and a large beta-sheet region in the upper part and at least four alpha-helices spliced together, indicating the similarity with collagen. The structural integrity of Enaptin can be shown by determining whether the protein forms a condensed supramolecule.

The molecular weight of the mature protein is approximately 1,011,041.95 Da, and it has a theoretical pI of 5.38 [1]. The following results do not take into account any annotated post-translational modification. The protein's chemical formula is C₄₄₁₈₉H₇₁₂₅₂N₁₂₄₂₈O₁₄₀₀₇S₃₂₁. It has a theoretical Instability Index (II) of 51.63, indicating that it would be unstable in a test tube. The protein's in vivo half-life, the time it takes for half of the amount of protein in a cell to disappear after its synthesis in the cell, is predicted to be approximately 30 hours (in mammalian reticulocytes). [2]

The protein is made up of three main parts, as can be seen in the diagram: cytoplasmic (1-8746), anchor for type IV membrane protein (8747-8767), and the sequence for perinuclear space (8768-8797). The region in the perinuclear space contains a KASH domain (Klarsicht, ANC-1, Syne Homology).

Amino acid composition

The following table lists the amino acids present in the protein in alphabetical order, along with a count of each, and its contribution to the total count (determined either by weight of the hydrosylate or by decomposition of the isolated amino acids).

Ala	(A)	571	6.5%
Arg	(R)	425	4.8%
Asn	(N)	289	3.3%
Asp	(D)	465	5.3%
Cys	(C)	117	1.3%
Gln	(Q)	763	8.7%
Glu	(E)	971	11.0%
Gly	(G)	290	3.3%
His	(H)	238	2.7%
Ile	(I)	391	4.4%
Leu	(L)	1148	13.0%
Lys	(K)	697	7.9%
Met	(M)	204	2.3%
Phe	(F)	206	2.3%
Pro	(P)	176	2.0%
Ser	(S)	730	8.3%
Thr	(T)	413	4.7%
Trp	(W)	131	1.5%
Tyr	(Y)	142	1.6%
Val	(V)	430	4.9%
Source: [3]

References

• Qiuping Zhang1, Jeremy N. Skepper, Fangtang Yang, John D. Davies1, Laszlo Hegyi, Roland G. Roberts, Peter L. Weissberg, Juliet A. Ellis and Catherine M. Shanahan (2001) Nesprins: a novel family of spectrin-repeat-containing proteins that localize to the nuclear membrane in multiple tissues. J Cell Sci. 2001; 114(Pt 24): 4485-98 (Free full text)
• R. Mark Grady, Daniel A. Starr, Gail L. Ackerman, Joshua R. Sanes, and Min Han (2005) Syne proteins anchor muscle nuclei at the neuromuscular junction PNAS. 2005; 102(12): 4359–64 (Free full text)

External links

• GeneReview/NCBI/NIH/UW entry on SYNE1-Related Autosomal Recessive Cerebellar Ataxia

See also

• Longest word in English
• Protein
• Titin Also a long-named, large protein
• Acetylseryltyrosylseryliso...serine Another large, long-named protein