Add sheet_directions

src/AssigningSecondaryStructure.jl

@@ -4,5 +4,7 @@ include("utils.jl")
 include("hydrogen.jl")
 include("dssp.jl")
 include("assign.jl")
+include("arrangement.jl")
+# TODO: sheet topology
 
 end

src/assign.jl

@@ -31,8 +31,13 @@ end
 import Backboner, Backboner.Protein
 import Backboner.Protein: ncaco_coords, readpdb
 
-assign_secondary_structure(chains::Vector{Protein.Chain}) = assign_secondary_structure(ncaco_coords.(chains))
+get_coords(chains::Vector{Protein.Chain}) = cat(ncaco_coords.(chains)..., dims=3)
+get_coords(chain::Protein.Chain) = get_coords([chain])
 
+assign_secondary_structure(chains::Vector{Protein.Chain}) = assign_secondary_structure(ncaco_coords.(chains))
 assign_secondary_structure(chain::Protein.Chain) = assign_secondary_structure([chain])[1]
 
+assign_secondary_structure(backbones::Vector{Backboner.Backbone}) = assign_secondary_structure(Backboner.Protein.Chain.(backbones))
+assign_secondary_structure(backbone::Backboner.Backbone) = assign_secondary_structure(Protein.Chain(backbone))
+
 assign_secondary_structure(filename::AbstractString) = assign_secondary_structure(readpdb(filename))

src/directions.jl

@@ -0,0 +1,8 @@
+export sheet_directions
+
+function sheet_directions(hbond_map::AbstractMatrix{<:Real})
+    p_bridge, a_bridge = get_bridges(hbond_map)
+    vec(sum(p_bridge, dims=2)), vec(sum(a_bridge, dims=2))
+end
+
+sheet_directions(chains::Union{Protein.Chain, Vector{Protein.Chain}}) = sheet_directions(get_hbond_map(get_coords(chains)))

src/dssp.jl

@@ -14,21 +14,7 @@ function _unfold(a::AbstractArray, window::Int, axis::Int)
     return _moveaxis(unfolded, axis, ndims(unfolded))
 end
 
-# not differentiable like the PyDSSP version cause we use bitwise operators
-function dssp(coords::AbstractArray{T, 3}) where T
-    size(coords, 1) == 3 || throw(DimensionMismatch("Expected 3 coordinates per atom, got $(size(coords, 1))"))
-    size(coords, 2) == 4 || throw(DimensionMismatch("Expected 4 atoms per residue, got $(size(coords, 2))"))
-
-    N = size(coords, 3)
-    if N < 6
-        coords = cat(coords, fill(Inf, 3, 4, 6-N), dims=3)
-    end
-
-    coords = permutedims(coords, (3, 2, 1))
-
-    hbmap = get_hbond_map(coords)
-    hbmap = permutedims(hbmap, (2, 1))  # Rearrange to "i:C=O, j:N-H" form
-
+function get_helix_bools(hbmap::AbstractMatrix{<:Real})
     # Identify turn 3, 4, 5
     turn3 = diag(hbmap, 3) .> 0
     turn4 = diag(hbmap, 4) .> 0
@@ -46,7 +32,13 @@ function dssp(coords::AbstractArray{T, 3}) where T
 
     helix3 = h3 .| circshift(h3, 1) .| circshift(h3, 2)
     helix5 = h5 .| circshift(h5, 1) .| circshift(h5, 2) .| circshift(h5, 3) .| circshift(h5, 4)
+
+    helix = helix3 .| helix4 .| helix5
+
+    return helix
+end
 
+function get_bridges(hbmap::AbstractMatrix{<:Real})
     # Identify bridge
     unfoldmap = _unfold(_unfold(hbmap, 3, -2), 3, -2) .> 0
     unfoldmap_rev = permutedims(unfoldmap, (2, 1, 3, 4))
@@ -57,12 +49,31 @@ function dssp(coords::AbstractArray{T, 3}) where T
     a_bridge = (unfoldmap[:, :, 2, 2] .& unfoldmap_rev[:, :, 2, 2]) .| (unfoldmap[:, :, 1, 3] .& unfoldmap_rev[:, :, 1, 3])
     a_bridge = _pad(false, a_bridge, (1,1), (1,1))
 
-    # Ladder
-    ladder = dropdims(reduce(|, p_bridge .| a_bridge, dims=2), dims=2)
+    return p_bridge, a_bridge
+end
+
+function get_ladder_bools(hbmap::AbstractMatrix{<:Real})
+    p_bridge, a_bridge = get_bridges(hbmap)
+    ladder = vec(reduce(|, p_bridge .| a_bridge, dims=2))
+    return ladder
+end
+
+# not differentiable like the PyDSSP version cause we use bitwise operators
+function dssp(coords::AbstractArray{T, 3}) where T
+    size(coords, 1) == 3 || throw(DimensionMismatch("Expected 3 coordinates per atom, got $(size(coords, 1))"))
+    size(coords, 2) == 4 || throw(DimensionMismatch("Expected 4 atoms per residue, got $(size(coords, 2))"))
+
+    N = size(coords, 3)
+    if N < 6
+        coords = cat(coords, fill(Inf, 3, 4, 6-N), dims=3)
+    end
+
+    hbmap = get_hbond_map(coords) # "i:C=O, j:N-H" form
+
     # H, E, L of C3
-    helix = helix3 .| helix4 .| helix5
-    strand = ladder
-    loop = .!helix .& .!strand
+    helix = get_helix_bools(hbmap)
+    strand = get_ladder_bools(hbmap)
+    loop = .!(helix .| strand)
 
     num_vector = findfirst.(eachrow(hcat(loop, helix, strand)))[1:N]
 

src/hydrogen.jl

@@ -1,24 +1,29 @@
-function get_hydrogen_positions(coords::AbstractArray{T, 3}) where T <: Real
-    vec_cn = coords[2:end, 1, :] .- coords[1:end-1, 3, :]
+function get_hydrogen_positions(coords::AbstractArray{T, 3}; permute=true) where T <: Real
+    _, atoms_per_residue, residue_count = size(coords)
+    atoms_per_residue == 4 || throw(DimensionMismatch("Expected 4 atoms per residue, got $atoms_per_residue"))
+    permute && (coords_p = permutedims(coords, (3, 2, 1)))
+    vec_cn = coords_p[2:end, 1, :] .- coords_p[1:end-1, 3, :]
     vec_cn ./= mapslices(norm, vec_cn, dims=2)
-    vec_can = coords[2:end, 1, :] .- coords[2:end, 2, :]
+    vec_can = coords_p[2:end, 1, :] .- coords_p[2:end, 2, :]
     vec_can ./= mapslices(norm, vec_can, dims=2)
     vec_nh = vec_cn .+ vec_can
     vec_nh ./= mapslices(norm, vec_nh, dims=2)
-    return coords[2:end, 1, :] .+ 1.01 .* vec_nh
+    return coords_p[2:end, 1, :] .+ 1.01 .* vec_nh
 end
 
 function get_hbond_map(
     coords::AbstractArray{T, 3};
     cutoff::Float64 = DEFAULT_CUTOFF,
     margin::Float64 = DEFAULT_MARGIN,
 ) where T <: Real
-    residue_count, atoms_per_residue, _ = size(coords)
+    _, atoms_per_residue, residue_count = size(coords)
     atoms_per_residue == 4 || throw(DimensionMismatch("Expected 4 atoms per residue, got $atoms_per_residue"))
 
-    cpos = coords[1:end-1, 3, :]
-    opos = coords[1:end-1, 4, :]
-    npos = coords[2:end, 1, :]
+    coords_p = permutedims(coords, (3, 2, 1))
+
+    cpos = coords_p[1:end-1, 3, :]
+    opos = coords_p[1:end-1, 4, :]
+    npos = coords_p[2:end, 1, :]
     hpos = get_hydrogen_positions(coords)
 
     cmap = repeat(reshape(cpos, 1, :, 3), outer=(residue_count-1, 1, 1))
@@ -50,5 +55,5 @@ function get_hbond_map(
     hbond_map .= (sin.(hbond_map .* (π / 2 / margin)) .+ 1.0) ./ 2.0
     hbond_map .*= local_mask
 
-    return hbond_map
+    return hbond_map'
 end

test/runtests.jl

@@ -30,4 +30,12 @@ ss_composition(ss::Vector{Int}) = [count(==(code), ss) for code in 1:3]
 
     end
 
+    @testset "sheet arrangement" begin
+        hbond_map = ASS.get_hbond_map(ASS.ncaco_coords.(ASS.readpdb("data/1ASS.pdb"))[1])
+        p, ap = sheet_arrangement(hbond_map)
+        @test p isa Vector{Int64}
+        @test Set(unique(p))  == Set([0, 1, 2])
+        @test Set(unique(ap)) == Set([0, 1, 2])
+    end
+
 end