ELMKIAQLAKRGP
HHHHHHHHHHH--
VVICETTWYVEVT
+-+-+-+-+-+-+
Strand? + is out; - is in. One T points in, further all is OK. Many VITWYF residues.
A few hydrophobics point out but that is allowed. So: Strand!
VTITVEGPKITVE
-+-+-+TT+-+-+
β-hairpin? + is out; - is in and those are OK. Turn is GP is also OK. So, Hairpin!
SRGGEPTRHEAKE
---------HHHH
Beginning is a mess. End can be helical, but 4 residues seems not much to decide that
something might be a helix. So, perhaps the beginning of a helix, but very perhaps.
ELLALKLLTVTVT
HHHHHHHHSSSSS 1
HHHHHHH-SSSSS 2
HHHHHHHH-SSSS 3
But you normally need HHH-SSS so solution 2 or 3. Look up Chou and Fasman parameters.
L is more 'expensive' in a helix than T in a strand. So, solution 3.