. 2010 Jul 29;68(2):169–184. doi: 10.1007/s00018-010-0462-z

Table 1.

Characteristics of spider silks and spidroins

Gland	Function	Spidroin	Architecture	Length (residues)^a	Amino acid motifs	Ensemble repeat length (residues)
Major ampullate	Web frame, life line	MaSp1	NT-REP-CT	3,130	A_n, GX and GGX^b	~30
Major ampullate	Web frame, life line	MaSp2	NT-REP-CT	3,780	A_n, GGX, GPX, QQ, GSG^b	~30
Minor ampullate	Web reinforce-ment, capture silk	MiSp1	U-REP-CT	nd	GGX, (GA)_n, A_n, spacer (137 residues)^c	~280, Spacer[(GGX)_n(GA)_yA_z]₁₀; similar to MiSp1
Minor ampullate	Web reinforce-ment, capture silk	MiSp2	U-REP-CT	nd	GGX, (GA)_n, A_n, spacer (137 residues)^c	~280, Spacer[(GGX)_n(GA)_yA_z]₁₀; similar to MiSp1
Flagelliform	Capture spiral	Flag	NT-REP-CT	~5,000	GPGG(X)_n, GGX, spacer (~28 residues)^d	~440
Aciniform	Wrapping silk, inner egg case	AcSp1	U-REP-CT	nd	S_n, TGPSG^e	200
		AcSp1			S_n, GPS^m	~350
		AcSp1-like			GGX^f	~187
Tubuliform/cylindriform	Outer egg case	TuSp1	NT-REP-CT	2,983	Short A_n, S_n, T_n, (SX)^g_n	171–182
		TuSp1			Short A_n, S_n, T_n, (SX)^h_n	180, [A₀B₁(A₁B₁)_nA₂]_, A₁ = 139, B₁ = 41
		TuSp1			Short A_n, S_n,T_n, (SX)^i,k_n	184
		TuSp1			Short A_n, S_n, T_n, (SX)^l,l_n	161, [B₀(A₁B₁)_nA₂]_, B₀ = 48, A₁ = 110, B₁ = 61, A₂ = 98
		TuSp1			Short A_n, S_n, T_n, (SX)^m_n	~200
		TuSp1			Short A_n, S_n, T_n, (SX)^m_n	~300
		TuSp1			Short A_n, S_n, T_n, (SX)ⁿ_n	174
		TuSp2	NT-REP-CT	3,218	Short A_n, S_n, T_n, (SX)^h_n	180, [A₀B₁(A₁B₁)_nA₂]_, A₁ = 139, B₁ = 41
		ECP-1	Z-REP	932	(GA)_n, short A^j_n in parts of sequence	na^q
		ECP-2	Z-REP	825	(GA)_n, short A^k_n in parts of sequence	na^q
Aggregate	Sticky coating	SCP-1	na	36	na^o	na
Aggregate	Sticky coating	SCP-2	na	19	na^o	na
Pyriform	Attachment disk, joining fibre	PySp1	U-REP-CT	nd	AAARAQAQAEARAKAE (A₁), AAARAQAQAE (A₂) and a 78 residue iteration (A₃)^p	[(A₁A₂)_nA₃]_n

na Not applicable, nd not determined, X any amino acid residue, U unknown N-terminal sequence, Z the ECP N-terminal region is approx.150 amino acid residues long, non-repetitive and contains 16 Cys but is not homologous to other spidroin N-terminal domains

Sources/references for amino acid motifs and ensemble repeat length (residues): ^b [22] (Latrodectus hesperus), ^c [116] (Nephila clavipes), ^d [46] (Nephila clavipes, Nephila madagascariensis), ^e [117] (Argiope trifasciata), ^f [118] (Latrodectus hesperus), ^g [119] (Argipoe aurantatia, Nephila clavipes, Araneus gemmoides), ^h [45] (Argiope bruennichi), ^I [120] (Latrodectus hesperus), ^j [121] (Latrodectus hesperus), ^k [122] ( Latrodectus hesperus), ^l [123] (Nephila clavata), ^m [35] (Deinopis spinosa, Uloborus diversus), ⁿ [124] (Nephilengys cruentata), ^o [125] (Latrodectus hesperus), ^p [126] (Latrodectus hesperus), ^q ECP-1 and -2 are considered to be atypical since they are much shorter than other known full-length spidroins (approximately 800–1,000 amino acid residues) and lack higher ensemble repeat units

^a Length in amino acid residues. Full-length gene sequences are available for MaSp1 and MaSp2 from Latrodectus Hesperus, Nephila flagelliform silk and for the cDNAs of CySp1 and CySp2 from Argiope bruennichi